Winding forming method of ultrathin carbon-carbon screen blank

Abstract

The invention discloses a winding forming method of an ultrathin carbon-carbon screen blank. The winding forming method comprises the following steps: selecting a fiber reinforcement material meeting the lowest multifilament strength and a resin matrix material meeting the residual carbon rate index; formulating a winding system; a fiber-reinforced resin-based composite material is obtained according to the fiber-reinforced body material and the resin matrix material, and the fiber-reinforced resin-based composite material is cured and mechanically processed according to a winding system to obtain an ultrathin carbon-carbon screen blank. According to the preparation method, the ultrathin carbon-carbon screen blank which can meet index requirements can be prepared, and the quality is reliable.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-thin carbon-carbon screen blanks, and in particular relates to a winding forming method of an ultra-thin carbon-carbon screen blank. Background Art

[0002] The level of spacecraft manufacturing is an important reference for measuring a country's comprehensive national strength. With the gradual advancement of my country's major aerospace projects such as deep space exploration, higher requirements have been placed on the lifespan, reliability and other indicators of new-generation spacecraft such as deep space probes and large-capacity satellites. Traditional chemical propulsion systems are increasingly unable to meet the needs of deep space exploration missions.

[0003] In response to the new situation of deep space exploration, long-life electric propulsion ion engines have become the preferred propulsion system for the new generation of spacecraft. The working principle of electric propulsion ion engines is to first use electrical energy to ionize the propellant. The ionized ions are accelerated and drawn out in the process of passing through the grid assembly with an ultra-thin mesh structure, thereby generating long-term stable thrust. Among them, the grid assembly is the core component of the electric propulsion ion engine, and its design and manufacturing level directly determines the performance and life of the propulsion system.

[0004] At present, my country has broken through the key manufacturing technology of conventional metal molybdenum grids, but the service life is only 14,000 hours, which is still a huge gap from the 4,000-hour service life requirement for deep space exploration. In order to improve the structural performance of ultra-thin mesh structure grid components, further research on the application of advanced materials must be carried out. Carbon-carbon composite materials are an ideal choice to replace metal molybdenum as the material for the grid components of electric propulsion ion engines. However, there are technical barriers when winding carbon-carbon composite materials into ultra-thin carbon-carbon mesh blanks. Ultra-thin carbon-carbon mesh blanks are prone to fractures in the thickness direction due to thickness limitations. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide a winding forming method for an ultra-thin carbon-carbon screen blank, which can prepare an ultra-thin carbon-carbon screen blank that can meet index requirements and has reliable quality.

[0006] The object of the present invention is achieved through the following technical scheme: a winding molding method for an ultra-thin carbon-carbon screen blank, comprising: selecting a fiber reinforcement material that meets the minimum multifilament strength and a resin matrix material that meets the residual carbon rate index; formulating a winding system; obtaining a fiber-reinforced resin-based composite material based on the fiber reinforcement material and the resin matrix material, and curing and mechanically processing the fiber-reinforced resin-based composite material according to the winding system to obtain an ultra-thin carbon-carbon screen blank.

[0007] In the winding forming method of the ultra-thin carbon-carbon screen blank, the minimum multifilament strength of the fiber reinforcement material is obtained by the following formula:

[0008]

[0009] Among them, σ is the minimum multifilament strength of the fiber reinforcement material, k1 is the first coefficient, w is the opening rate, m is the maximum weight allowed by the ultra-thin carbon-carbon screen blank; g is the standard gravity acceleration; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; h is the thickness value of the ultra-thin carbon-carbon screen blank.

[0010] In the winding forming method of the ultra-thin carbon-carbon screen blank, the residual carbon rate of the resin matrix material is ≥55%.

[0011] In the winding forming method of the ultra-thin carbon-carbon screen blank, the winding system includes: the number of winding layers, the winding sequence and the winding tape distance.

[0012] In the winding forming method of the ultra-thin carbon-carbon screen blank, the number of winding layers is 6.

[0013] In the winding forming method of the ultra-thin carbon-carbon screen blank, the winding sequence is 0°, 60°, 120°, 60°, 120°, 0°.

[0014] In the winding forming method of the ultra-thin carbon-carbon screen blank, the winding tape distance is obtained by the following formula:

[0015]

[0016] Among them, b is the winding tape distance, k2 is the second coefficient, m is the maximum weight allowed for the ultra-thin carbon-carbon screen blank; l is the unfolded bandwidth during the winding process of the fiber reinforcement material; t is the linear density value of the fiber reinforcement material; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; n is the number of winding layers.

[0017] In the above-mentioned winding molding method of the ultra-thin carbon-carbon screen mesh blank, the fiber-reinforced resin-based composite material is cured and mechanically processed according to a winding system to obtain an ultra-thin carbon-carbon screen mesh blank, including: winding the fiber-reinforced resin-based composite material on a mold tooling according to a winding system, placing the fiber-reinforced resin-based composite material together with the mold tooling into a curing device and curing it according to the curing system; after the curing is completed and waiting for natural cooling, the fiber-reinforced resin-based composite material together with the mold tooling is taken out, and mechanical processing is performed according to a preset ultra-thin carbon-carbon screen mesh blank shape and size to obtain an ultra-thin carbon-carbon screen mesh blank.

[0018] In the above-mentioned winding forming method of the ultra-thin carbon-carbon screen mesh blank, the mold tooling is a hexagonal winding tooling; wherein, the six corners of the hexagonal winding tooling are respectively processed with a first tightening hole, a second tightening hole, a third tightening hole, a first fixing screw hole, a second fixing screw hole and a third fixing screw hole.

[0019] In the winding molding method of the above-mentioned ultra-thin carbon-carbon screen mesh blank, the curing system is to maintain the temperature at 60°C for 3 hours and then increase the temperature to 105°C, maintain the temperature at 105°C for 4 hours and then increase the temperature to 135°C, maintain the temperature at 135°C for 4 hours and then increase the temperature to 165°C, maintain the temperature at 165°C for 3 hours and then naturally cool down to room temperature.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention uses a specific empirical formula to calculate the minimum multifilament strength index that the reinforcement fiber material needs to meet, thereby ensuring that the ultra-thin carbon-carbon screen blank is not prone to breakage during subsequent processing;

[0022] (2) The present invention determines a type of reliable matrix material, thereby ensuring that the ultra-thin carbon-carbon screen has a high (≥55%) residual carbon rate after the carbonization process;

[0023] (3) The present invention uses a specific empirical formula to calculate the winding tape distance of the reinforcement fiber material, thereby ensuring that the finished blank meets the thickness index requirements;

[0024] (4) The present invention can prepare an ultra-thin carbon-carbon screen blank that meets index requirements and has reliable quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0026] Figure 1 Schematic diagram of a winding tooling for an ultra-thin carbon-carbon screen blank provided by an embodiment of the present invention;

[0027] Figure 2 yes Figure 1 Schematic diagram of the AA section. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] The process flow for preparing ultra-thin carbon-carbon mesh grid is roughly divided into three steps: blank forming, carbonization and finishing. Among them, the blank forming as the first step is particularly critical, which determines the difficulty of subsequent processes and the forming effect of the final product.

[0030] This embodiment is designed as follows Figure 1 The winding tooling of the ultra-thin carbon-carbon screen mesh blank shown in the figure, after completing the material selection and winding system design work, can use the tooling to finally obtain an ultra-thin carbon-carbon screen mesh blank whose fiber orientation and material thickness meet the design requirements through fiber winding and subsequent pressurization curing.

[0031] Ultra-thin carbon-carbon screen mesh blanks are prone to fracture through the thickness direction due to thickness limitations, so the stiffness of the finished product should be ensured by formulating selection criteria for the fiber materials of the blank reinforcement; during the preparation of the ultra-thin carbon-carbon screen mesh blanks, preparations should be made for the next carbonization process, and it is necessary to ensure that the blank still has a high residual carbon rate after the carbonization process; the thickness of the ultra-thin carbon-carbon screen mesh blanks has strict requirements, and the winding system of the ultra-thin carbon-carbon screen mesh blanks should be reasonably formulated according to their thickness conditions.

[0032] The present embodiment provides a winding molding method for an ultra-thin carbon-carbon screen blank, the method comprising: selecting a fiber reinforcement material that meets the minimum multifilament strength and a resin matrix material that meets the residual carbon rate index; formulating a winding system; obtaining a fiber-reinforced resin-based composite material based on the fiber reinforcement material and the resin matrix material, and curing and mechanically processing the fiber-reinforced resin-based composite material according to the winding system to obtain an ultra-thin carbon-carbon screen blank.

[0033] The minimum multifilament strength of fiber reinforcement materials is obtained by the following formula:

[0034]

[0035] Among them, σ is the minimum multifilament strength of the fiber reinforcement material, k1 is the first coefficient, w is the opening rate, m is the maximum weight allowed by the ultra-thin carbon-carbon screen blank; g is the standard gravity acceleration; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; h is the thickness value of the ultra-thin carbon-carbon screen blank.

[0036] The residual carbon rate of the resin matrix material is ≥55%.

[0037] The winding system includes: the number of winding layers, winding sequence and winding tape distance. The number of winding layers is 6. The winding sequence is 0°, 60°, 120°, 60°, 120°, 0°.

[0038] The winding tape distance is obtained by the following formula:

[0039]

[0040] Among them, b is the winding tape distance, k2 is the second coefficient, m is the maximum weight allowed for the ultra-thin carbon-carbon screen blank; l is the unfolded bandwidth during the winding process of the fiber reinforcement material; t is the linear density value of the fiber reinforcement material; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; n is the number of winding layers.

[0041] The method comprises curing and mechanically processing the fiber-reinforced resin-based composite material according to a winding system to obtain an ultra-thin carbon-carbon screen mesh blank, comprising: winding the fiber-reinforced resin-based composite material on a mold tooling according to the winding system, placing the fiber-reinforced resin-based composite material together with the mold tooling into a curing device and curing them according to the curing system; after the curing is completed and the temperature is naturally cooled, taking out the fiber-reinforced resin-based composite material together with the mold tooling, and mechanically processing and forming the ultra-thin carbon-carbon screen mesh blank according to a preset shape and size of the ultra-thin carbon-carbon screen mesh blank to obtain the ultra-thin carbon-carbon screen mesh blank.

[0042] like Figure 1 and Figure 2 As shown, the mold tooling is a hexagonal winding tooling, wherein the six corners of the hexagonal winding tooling are respectively processed with a first top tightening hole 1, a second top tightening hole 2, a third top tightening hole 3, a first fixing screw hole 4, a second fixing screw hole 5 and a third fixing screw hole 6. The winding tooling is fixed by switching different fixing screw holes and corresponding top tightening holes to complete the layered winding of composite materials in different winding directions.

[0043] The curing system is as follows: the temperature is maintained at 60°C for 3 hours and then increased to 105°C; the temperature is maintained at 105°C for 4 hours and then increased to 135°C; the temperature is maintained at 135°C for 4 hours and then increased to 165°C; the temperature is maintained at 165°C for 3 hours and then naturally cooled to room temperature.

[0044] The preparation and molding of the ultra-thin carbon-carbon screen blank requires the help of a winding tool. Taking the ultra-thin carbon-carbon screen blank with single-layer fiber winding angles of 0°, 60° and 120° as an example, the designed hexagonal winding tool is as follows Figure 1 As shown. Figure 2 It can be seen that the six corners of the hexagonal winding tooling are respectively processed with the first tightening hole 1, the second tightening hole 2, the third tightening hole 3, the first fixing screw hole 4, the second fixing screw hole 5, and the third fixing screw hole 6. By switching the winding tooling to different fixing screw holes and corresponding tightening holes for fixing, the layered winding of the composite material in different winding directions can be completed.

[0045] The process of preparing ultra-thin carbon-carbon screen blank includes the following steps:

[0046] (1) Selection of fiber reinforcement materials and resin matrix materials;

[0047] (2) the formulation of entanglement system;

[0048] (3) Curing and machining.

[0049] The specific implementation method is:

[0050] (1) Selection of fiber reinforcement materials and resin matrix materials

[0051] a) Based on the thickness, opening rate and outer diameter of the screen to be prepared, the minimum multifilament strength of the required fiber reinforcement material can be calculated according to the following empirical formula:

[0052]

[0053] Wherein, σ is the minimum multifilament strength value of the fiber reinforcement material; k1 is an empirical parameter, generally taken as 5 to 8; w is the opening ratio, that is, the ratio of the opening area to the opening region area (the sum of the opening area and the opening gap area); m is the maximum weight allowed for the ultra-thin carbon-carbon screen blank; g is the standard gravitational acceleration; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; h is the thickness value of the ultra-thin carbon-carbon screen blank.

[0054] According to the minimum multifilament strength value calculated by (1), it is only necessary to select fibers whose average multifilament strength test value is higher than this value. It is recommended to select fiber reinforcement materials from carbon fibers.

[0055] b) Through process verification, the use of phenolic resin as the matrix material of the ultra-thin carbon-carbon screen blank can ensure that the blank has a high (≥55%) residual carbon rate (i.e. the mass percentage of carbon element in the residue of the matrix material after the carbonization process) after the subsequent carbonization process. Other resins that can meet the residual carbon rate index can also be used as matrix materials.

[0056] (2) Formulation of winding system

[0057] c) Designing a winding system by taking an ultra-thin carbon-carbon screen blank including single-layer fiber winding angles of 0°, 60° and 120° as an example. First, the number of winding layers needs to be determined. It is recommended that the number of winding layers be no less than 2. In the case selected by the present invention, since the ultra-thin carbon-carbon screen blank is designed with 3 winding angles of 0°, 60° and 120°, it is recommended that the number of winding layers be set to 6;

[0058] d) For the design of the winding sequence of each winding layer, it is not recommended to wind the winding layers in the same direction together, so the winding sequence is set to 0°, 60°, 120°, 60°, 120°, 0°;

[0059] e) Based on the thickness of the finished blank, the unfolded bandwidth of the reinforcement fiber material, the width of the winding coverage area, the rubber content of the composite material and other parameters, the winding tape distance of the reinforcement fiber material can be calculated according to the following empirical formula:

[0060]

[0061] Wherein, b is the winding tape distance of the fiber reinforced material; k2 is an empirical parameter, generally taken as 0.75-0.95; m is the maximum weight allowed for the ultra-thin carbon-carbon screen blank; l is the unfolded bandwidth during the winding process of the fiber reinforced material; t is the linear density of the fiber reinforced material; d is the outer diameter of the ultra-thin carbon-carbon screen blank; n is the number of winding layers.

[0062] (3) Curing and machining

[0063] f) After the fiber-reinforced resin-based composite material is wound, the wound layer composite material together with the mold tooling can be placed in the curing equipment and cured according to the curing system of the selected resin material;

[0064] g) After the curing is completed and the temperature drops naturally, the composite material of the winding layer is taken out together with the mold tooling, and sent to be machined and formed according to the shape and size of the ultra-thin carbon-carbon screen blank. It is recommended to select the overlapping area of ​​each winding layer for machining and remove the edge composite material.

[0065] According to the strength value calculated by the empirical formula of the minimum multifilament strength of the required fiber reinforcement material, a certain brand of domestic T1000 grade carbon fiber was selected as the fiber reinforcement material; the selected resin was a certain brand of phenolic resin; the number of winding layers of the designed ultra-thin carbon-carbon screen blank composite material was 6, and the thickness was 0.75mm; according to the winding angles of different winding layers, the designed winding sequence was 0°, 60°, 120°, 60°, 120°, 0°; according to the empirical formula of the winding tape distance of the reinforcement fiber material, the winding tape distance was calculated to be 0.65mm; according to the relevant process parameters of the selected resin, the determined curing system was 60℃ / 3h→105℃ / 4h→135℃ / 4h→165℃ / 3h→natural cooling. A total of 8 ultra-thin carbon-carbon screen blanks were prepared, all of which passed the subsequent carbonization and vapor deposition processes, and the ultra-thin carbon-carbon screens finally obtained passed the thermal environment test and mechanical properties test assessment.

[0066] In this embodiment, according to the parameters such as the thickness, opening rate and outer diameter of the screen to be prepared, a specific empirical formula is substituted to calculate the minimum multifilament strength index that the reinforcement fiber material needs to meet; through process verification, the use of phenolic resin as the matrix material of the ultra-thin carbon-carbon screen blank can ensure that the blank has a high (≥55%) residual carbon rate after the subsequent carbonization process; according to the parameters such as the thickness of the finished blank, the unfolded bandwidth of the reinforcement fiber material, the width of the winding coverage area, the rubber content of the composite material, etc., the winding tape distance of the reinforcement fiber material is calculated by substituting into the specific empirical formula.

[0067] The present embodiment uses a specific empirical formula to calculate the minimum multifilament strength index that the reinforcement fiber material needs to meet, thereby ensuring that the ultra-thin carbon-carbon screen mesh blank is not prone to breakage during subsequent processing; the present embodiment determines a type of reliable matrix material, thereby ensuring that the ultra-thin carbon-carbon screen mesh has a high (≥55%) residual carbon rate after the carbonization process; the present embodiment uses a specific empirical formula to calculate the winding tape distance of the reinforcement fiber material, thereby ensuring that the finished blank meets the thickness index requirements; the present embodiment can prepare an ultra-thin carbon-carbon screen mesh blank that meets the index requirements and has reliable quality.

[0068] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A winding forming method for an ultra-thin carbon-carbon screen blank, characterized in that include: Select fiber reinforcement materials that meet the minimum multifilament strength and resin matrix materials that meet the carbon residue rate index; Establish a winding system; A fiber-reinforced resin-based composite material is obtained according to the fiber reinforcement material and the resin matrix material, and the fiber-reinforced resin-based composite material is solidified and mechanically processed according to a winding system to obtain an ultra-thin carbon-carbon screen blank.

2. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 1 is characterized in that: The minimum multifilament strength of fiber reinforcement materials is obtained by the following formula: Among them, σ is the minimum multifilament strength of the fiber reinforcement material, k1 is the first coefficient, w is the opening rate, m is the maximum weight allowed by the ultra-thin carbon-carbon screen blank; g is the standard gravity acceleration; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; h is the thickness value of the ultra-thin carbon-carbon screen blank.

3. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 1 is characterized in that: The residual carbon rate of the resin matrix material is ≥55%.

4. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 1 is characterized in that: The winding system includes: number of winding layers, winding sequence and winding tape distance.

5. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 4 is characterized in that: The number of winding layers is 6.

6. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 4 is characterized in that: The winding sequence is 0°, 60°, 120°, 60°, 120°, 0°.

7. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 4 is characterized in that: The winding tape distance is obtained by the following formula: Among them, b is the winding tape distance, k2 is the second coefficient, m is the maximum weight allowed for the ultra-thin carbon-carbon screen blank; l is the unfolded bandwidth during the winding process of the fiber reinforcement material; t is the linear density value of the fiber reinforcement material; d is the outer diameter value of the ultra-thin carbon-carbon screen blank; n is the number of winding layers.

8. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 1 is characterized in that: The fiber-reinforced resin-based composite material is solidified and mechanically processed according to the winding system to obtain an ultra-thin carbon-carbon screen blank including: Winding the fiber-reinforced resin-based composite material on the mold tooling according to the winding system, placing the fiber-reinforced resin-based composite material together with the mold tooling into a curing device and curing according to the curing system; After the curing is completed and the temperature is naturally lowered, the fiber-reinforced resin-based composite material is taken out together with the mold tooling, and the ultra-thin carbon-carbon screen blank is mechanically processed and formed according to the preset shape and size of the ultra-thin carbon-carbon screen blank to obtain the ultra-thin carbon-carbon screen blank.

9. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 8, characterized in that: The mold tooling is a hexagonal winding tooling; wherein the six corners of the hexagonal winding tooling are respectively processed with a first tightening hole (1), a second tightening hole (2), a third tightening hole (3), a first fixing screw hole (4), a second fixing screw hole (5) and a third fixing screw hole (6).

10. The winding forming method of the ultra-thin carbon-carbon screen blank according to claim 8, characterized in that: The curing system is as follows: the temperature is maintained at 60°C for 3 hours and then raised to 105°C, the temperature is maintained at 105°C for 4 hours and then raised to 135°C, the temperature is maintained at 135°C for 4 hours and then raised to 165°C, the temperature is maintained at 165°C for 3 hours and then naturally cooled to room temperature.

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