A method for preparing a hemispherical cover body based on a winding process

Abstract

The application discloses a kind of based on winding process hemispherical cover preparation method, belong to aerospace technical field, including the following steps: installation metal core mould, package sealing layer, set winding procedure, carbon fiber inner layer winding, pre-solidification, installation fixed foam interlayer, winding reinforcement layer, installation glass fiber plate interlayer, carbon fiber outer layer winding, solidification, cutting demoulding, machine adds.This application based on winding process hemispherical cover preparation method, both can guarantee product quality, can shorten production cycle, improve production efficiency, play the advantage of automatic equipment, compared with traditional manual laying method, after using winding process, degree of automation is higher, forming cycle is shorter, cost is lower;The hemispherical cover product prepared by the hemispherical cover preparation method of the application is integrally formed with the main body structure without opening end, and is not bonded by adhesive for secondary bonding, so that the product has better pressure bearing effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace, and particularly relates to a preparation method of a hemispherical cover body based on a winding process. BACKGROUND

[0002] Lightweight is an important trend in the development of advanced missile weapons, and the main measure to achieve lightweight is to widely use advanced composite materials and establish a key composite material design and manufacturing technology system for missiles. Advanced composite materials have excellent specific strength, specific stiffness, fatigue resistance and stiffness designability, and have been widely used in aerospace structures.

[0003] Composite material production belongs to a labor-intensive industry, and a large number of aerospace parts rely on manual laying for production. With the rapid development of the aerospace industry in recent years, the demand for hemispherical cover body launch seats has increased, and there is an urgent need for a low-cost, fast production forming method to replace the original manual laying process. The use of winding process can greatly shorten the production cycle and the quality deviation caused by uncontrollable human factors, but there is currently no winding forming method for producing hemispherical cover body products made of full composite material without openings.

[0004] Therefore, in view of the above problems, a preparation method of a hemispherical cover body based on a winding process is provided.

[0005] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general context in which the present application can be practiced. It is not admitted that any of the information provided in this BACKGROUND section constitutes prior art that is already known in the prior art. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a hemispherical cover body based on a winding process. Compared with the traditional manual laying method, the use of the winding process has higher automation, shorter forming cycle and lower cost. It can solve the problems of long cycle and high cost of manual laying of hemispherical cover body products without openings on one side.

[0007] In order to achieve the above purpose, the technical scheme provided by a specific embodiment of the present application is as follows:

[0008] A preparation method of a hemispherical cover body based on a winding process, comprising the following steps:

[0009] S1, winding core mold preparation work:

[0010] First, install the metal core mold on the winding machine, then wrap the sealing layer on the surface of the metal core mold, and then set the winding program of the winding machine;

[0011] S2, preparation of carbon fiber inner layer:

[0012] S2.1, carbon fiber inner layer winding: first, evenly brush a layer of winding resin on the surface of the thermal insulation layer, the first layer of spiral winding ensures that there is no opening end (no shaft end) overcut winding, no hole expansion, and the shaft end ensures that the carbon fiber yarn is hung on the metal core mold, then use the carbon cloth impregnated with resin to reinforce the no opening end (no shaft end), and the reinforcing area decreases by 50-80mm wide from the plane outer diameter;

[0013] The second layer of spiral winding ensures that the no opening end is expanded with the plane outer diameter as the opening diameter, and the carbon cloth impregnated with resin is used to fill and reinforce the center of the hole expansion area;

[0014] Repeat the above-mentioned second layer spiral winding process four times, check the flatness of the product, and use carbon cloth to fill and level the defect position after pre-solidification;

[0015] S3, intermediate layer installation;

[0016] The intermediate layer includes a foam layer, a reinforcing layer and a glass fiber plate layer, which are installed on the carbon fiber inner layer in sequence;

[0017] S4, carbon fiber outer layer preparation:

[0018] S4.1, carbon fiber outer layer winding: first, brush a layer of winding resin on the glass fiber plate, the first layer of spiral winding requires no opening end (no shaft end) overcut winding, no hole expansion, and the shaft end ensures that the carbon fiber yarn is hung on the metal core mold;

[0019] Use the glass fiber cloth impregnated with resin to reinforce the no opening end, and the reinforcing area decreases by 50-80mm wide from the plane outer diameter;

[0020] The second layer of spiral winding ensures that the no opening end is expanded with the plane outer diameter as the opening diameter, and the carbon cloth impregnated with resin is used to fill and reinforce the center of the hole expansion area;

[0021] Repeat the above-mentioned second layer spiral winding process two times, check the flatness of the product, and use carbon cloth to fill and level the defect position;

[0022] After the product is laid on the entire outside of two layers of carbon cloth, it is solidified;

[0023] S5, post-processing.

[0024] In one or more embodiments of the present application, in S1, the metal core mold is installed specifically including the following steps:

[0025] First, use the derrick to overturn the metal core mold horizontally and fix it on the mold tool, use the derrick to lift the mold tool to the winding machine, then manually assist the single shaft to be inserted on one side of the winding machine driving shaft and clamped, and use screws to tighten and fix;

[0026] The package sealing layer specifically comprises the following steps:

[0027] After the surface of the metal core mold is cleaned with ethyl acetate, a layer of polytetrafluoroethylene release cloth is laid on the surface, and 2-3 mm thick rubber is laid on the product cutting line, the lap joint position is chamfered and polished, a vacuum bag is laid on the surface of the entire thermal insulation layer, and pressure exhaust treatment is performed;

[0028] The setting of the winding program specifically comprises the following steps:

[0029] The carbon fiber yarn reel is installed on the yarn rack, the winding tension is set to 50 N / axis, the winding angle is set to 18°-20°, the little cutting point winding program is debugged, and the reaming radius is set to 25-45 mm;

[0030] The winding machine is started, the clamping stability is detected during the rotation of the driving shaft, the winding is stopped, and the mold tooling is removed.

[0031] In one or more embodiments of the present application, the vacuum degree of the vacuum bag is -80 kpa or lower.

[0032] In one or more embodiments of the present application, in S2, the pre-curing specifically comprises the following steps:

[0033] Two layers of glue absorbing cloth are laid on the product, and a layer of non-porous isolation film is wrapped, and a layer of non-opening spiral layer is wound with dry yarn for pressure;

[0034] The hoisting tooling and the rotary curing tooling are installed, and then transported to the oven and connected with the oven rotary device, so that rotary heating pre-curing can be performed.

[0035] In one or more embodiments of the present application, the pre-curing temperature is 100-120℃, and the time is 6-8h.

[0036] In one or more embodiments of the present application, in S4, the curing specifically comprises the following steps:

[0037] Two layers of glue absorbing cloth are laid on the product before curing, and a layer of non-porous isolation film is wrapped, and a layer of non-opening spiral layer is wound with dry yarn for pressure;

[0038] The hoisting tooling and the rotary curing tooling are installed, and then transported to the oven and connected with the oven rotary device, so that rotary heating curing can be performed.

[0039] In one or more embodiments of the present application, the curing temperature is 140-160℃, and the time is 6-8h.

[0040] In one or more embodiments of the present application, the rotary speed of the pre-curing and the curing is 5-10 r / min, and the temperature rising and falling speed is not greater than 2℃ / min.

[0041] In one or more embodiments of the present application, in S2 and S4, the winding resin is an epoxy resin, and the ratio of the epoxy resin to the curing agent is 3:1.

[0042] In one or more embodiments of the present application, in S5, the post-processing includes cutting and demolding and machining.

[0043] Compared with the prior art, the hemispherical cover preparation method based on the winding process can ensure product quality, shorten the production cycle, improve production efficiency, take advantage of automatic equipment, and has a lower cost.

[0044] The hemispherical cover product prepared by the hemispherical cover preparation method has an opening end integrally formed with the main body structure and is not secondarily bonded by an adhesive, and has a better pressure bearing effect. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0046] Figure 1 The method flow chart of the hemispherical cover preparation method based on the winding process in an embodiment of the present application;

[0047] Figure 2 The hemispherical cover body structure diagram of the hemispherical cover preparation method based on the winding process in an embodiment of the present application;

[0048] Figure 3 The hemispherical cover body sectional view of the hemispherical cover preparation method based on the winding process in an embodiment of the present application;

[0049] Figure 4 The foam interlayer sectional view of the hemispherical cover preparation method based on the winding process in an embodiment of the present application;

[0050] Figure 5 The metal core mold structure diagram of the hemispherical cover preparation method based on the winding process in an embodiment of the present application.

[0051] MAIN REFERENCE NUMERALS EXPLANATION:

[0052] 1, hemispherical cover body; 2, carbon fiber inner layer; 3, foam interlayer; 4, glass fiber plate interlayer; 5, reinforcing layer; 6, carbon fiber outer layer; 7, metal core mold. DETAILED DESCRIPTION

[0053] In order for those skilled in the technical field to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should fall within the scope of protection of the present application.

[0054] As shown in the figure, the preparation method of the hemispherical cover body based on the winding process in an embodiment of the present application comprises the following steps: Figures 1-5

[0055] S1, installing the metal core mold 7:

[0056] First, the metal core mold 7 is flipped horizontally using a truss crane and fixed on a mold tool, the mold tool is hoisted to the winding machine using the truss crane, then the single shaft is manually inserted on one side of the winding machine driving shaft and clamped, and the screw is tightened for fixation;

[0057] Start the winding machine, detect the clamping stability during the rotation of the driving shaft, stop winding, and remove the mold tool.

[0058] S2, wrapping the sealing layer:

[0059] After the surface of the metal core mold 7 is cleaned with ethyl acetate, a layer of polytetrafluoroethylene release cloth is laid, and 2-3mm thick rubber is laid within the product cutting line, the lap joint position is chamfered and polished, a vacuum bag is punched on the entire thermal insulation layer surface, and pressure exhaust treatment is performed.

[0060] Preferably, the vacuum degree of the vacuum bag is below -80kpa.

[0061] S3, setting the winding program:

[0062] The carbon fiber yarn reel is installed on the yarn rack, the winding tension is set to 50N / axis, the winding angle is set to 18°-20°, the little cutting point winding program is debugged, and the hole expansion radius is set to 25-45mm.

[0063] S4, carbon fiber inner layer 2 winding:

[0064] First, a layer of winding resin is uniformly brushed on the surface of the thermal insulation layer, the first layer of spiral winding is ensured to have no open end (no shaft end) overcut winding, no hole expansion, and the shaft end is ensured to hang the carbon fiber yarn on the metal core mold 7, then the carbon cloth impregnated with resin is used to reinforce the no open end (no shaft end), and the reinforcement area decreases by 50-80mm wide outside the plane.

[0065] ​The second layer of spiral winding ensures that there is no open end, and the planar outer diameter is used as the opening diameter. After expanding, the carbon cloth impregnated with resin is used to fill and reinforce the center of the expanded area.

[0066] The above-mentioned second layer of spiral winding process is repeated four times, the flatness of the product is checked, and the defect position is filled with carbon cloth to make it flat.

[0067] S5, pre-curing:

[0068] Two layers of glue absorbing cloth are laid on the product, and then one layer of non-porous isolation film is wrapped. Dry yarn is used to wrap one layer of spiral layer without opening for pressure.

[0069] Install special lifting tooling and rotary curing special tooling, then transfer to the oven and connect with the oven rotary device, and then perform rotary heating pre-curing.

[0070] Preferably, the pre-curing temperature is 100-120℃, and the time is 6-8h.

[0071] S6, install foam interlayer 3:

[0072] The foam piece is tried on along the installation line and marked. If it is not conformal, the foam piece is polished smooth.

[0073] The foam piece is dehumidified and dried, and then a layer of structural adhesive film is pasted on the inner and outer surfaces of the foam piece. The foam piece is pasted one by one according to the marked position of the trial installation. After pasting, use adhesive tape to fix the shape and complete the installation of the foam interlayer 3.

[0074] Preferably, the foam piece dehumidification and drying treatment temperature is 100-120℃, and the time is 2-3h.

[0075] S7, winding reinforcement layer 5:

[0076] The ring winding is set, and a layer of impregnated carbon cloth is laid every certain thickness in the reinforcement area without interruption to obtain the reinforcement layer 5. Due to the large thickness of the reinforcement area, the impregnated carbon cloth is wound layer by layer.

[0077] Preferably, the ring winding requires more than 100mm than the theoretical width.

[0078] S8, install glass fiber plate interlayer 4:

[0079] The glass fiber plate is directly buckled on the product for trial installation. If it is not conformal, mark the non-conformal position.

[0080] The glass fiber plate is dehumidified and dried at 80-100℃ for 2-3h, and then the installation area of the glass fiber plate is polished and cleaned, and two layers of glass cloth are laid. Then the glass fiber plate is buckled on the installation position and tightened with fiber clamps.

[0081] S9, carbon fiber outer layer 6 windings:

[0082] First, apply a layer of winding resin to the fiberglass board. The first layer of spiral winding requires no open end (no shaft end) and over-cut winding, without enlarging the hole. The shaft end is sufficient to ensure that the carbon fiber yarn is hung on the metal core mold 7.

[0083] Reinforce the unopened end with resin-impregnated fiberglass cloth, with the reinforcement area decreasing in width from 50-80mm beyond the outer diameter of the plane.

[0084] The second layer of spiral winding ensures that the unopened end is wound with the outer diameter of the plane as the diameter after opening, and the center of the enlarged area is filled and reinforced with resin-impregnated fiberglass cloth.

[0085] Repeat the second spiral winding process twice, check the flatness of the product, and fill any defects with carbon cloth to make them smooth.

[0086] The entire outer side of the product is covered with two layers of carbon cloth.

[0087] Preferably, in S4 and S9, the winding resin is epoxy resin, and the ratio of epoxy resin to curing agent is 3:1.

[0088] S10, Curing:

[0089] Before curing, two layers of absorbent cloth are laid on the product, then a layer of non-porous release film is wrapped around it, and a layer of non-open spiral layer is wrapped with dry yarn to apply pressure;

[0090] Install the hoisting fixture and the rotary curing fixture, then transfer them to the oven and connect them to the oven's rotating device for rotary heating and curing.

[0091] Preferably, the curing temperature is 140-160℃ and the curing time is 6-8h.

[0092] More preferably, in S5 and S10, the rotation speed for pre-curing and curing is 5-10 r / min, and the heating and cooling rate is no more than 2℃ / min.

[0093] S11, Cutting and demolding:

[0094] After cleaning the auxiliary materials on the outside of the product, locate the cutting area, then use a cutting machine to cut the product, and use a jack to push the product out and demold it.

[0095] S12, Machining:

[0096] Install the product on the machining auxiliary fixture, fix and align it, then program and machine the product on a five-axis CNC machine tool to obtain the final product, the hemispherical cover body 1.

[0097] The carbon fiber used above is domestically produced T700 grade 12k carbon fiber, the resin used is epoxy resin system, and the foam is PMI foam.

[0098] In practical use, it will be as follows Figure 5 The metal core mold 7 shown is installed on the winding machine and clamped in place.

[0099] More preferably, to ensure the center balance of the metal core mold 7 during rotation, a shaft support bracket is added to the winding machine.

[0100] Clean the metal core mold 7 thoroughly, cover the entire mold surface with release cloth, cut 2mm thick sealing rubber and apply it to the entire product area, vacuum and degas the air, and then apply epoxy resin to the sealing layer.

[0101] After the carbon fiber yarn is arranged, set the yarn tension to 50N / axis and set the winding program to wind the inner layer.

[0102] More preferably, the winding process is set to a single tangent point.

[0103] The first layer of spiral winding, without openings, wraps the entire product area. Resin-impregnated carbon cloth is used to reinforce the unopened ends, with the reinforcement area decreasing in width from 50-80mm beyond the outer diameter of the plane. The second layer of spiral winding requires the unopened ends to be wound with the outer diameter of the plane as the opening diameter. Then, resin-impregnated carbon cloth is used to fill the center of the enlarged area. The above winding process is repeated four times to complete the inner layer 2 of carbon fiber winding.

[0104] Then, pre-curing is performed at a temperature of 100-120℃ for 6-8 hours.

[0105] More preferably, a conformal fixture is added to the unopened end during curing.

[0106] Install on the pre-cured product, such as Figure 3 and Figure 4 The foam interlayer 3, fiberglass interlayer 4, and reinforcing layer 5 shown are finished by smoothing and flattening the entire surface before continuing to wrap the outer layer.

[0107] The first layer of outer spiral winding requires no open end (no shaft end) over-wound without enlarging the hole; for the shaft end, ensure it holds the carbon fiber yarn on the mandrel. Then, use resin-impregnated fiberglass cloth to reinforce the open end, with the reinforcement area decreasing in width from 50-80mm beyond the outer diameter of the plane. The second layer of spiral winding requires the open end to be wound with the outer diameter of the plane as the diameter after opening, and the center of the enlarged area is filled with resin-impregnated fiberglass cloth. Repeat the above process twice to complete the outer layer 6 of carbon fiber winding.

[0108] Check the flatness of the product, fill the defective areas with carbon cloth to make them flat, and cover the entire outer side of the product with two layers of carbon cloth.

[0109] The final curing temperature is 140-160℃, the curing time is 6-8h, and the heating and cooling rate is no more than 2℃ / min.

[0110] Preferably, the actual curing temperature is increased by temperature steps: 80℃, 100℃, 120℃, and held for 1-2 hours.

[0111] The product is cut along the cutting lines using a cutting tool, and connecting holes are machined on a five-axis CNC machine to obtain the desired product. Figure 1 The hemispherical cover body 1 shown.

[0112] Compared with existing technologies, the hemispherical cover preparation method based on the winding process of this invention can not only ensure product quality, but also shorten the production cycle by 50%-60%, improve production efficiency, give full play to the advantages of automated equipment, and reduce costs.

[0113] The hemispherical cover product prepared by the hemispherical cover preparation method of the present invention has no open end and is integrally formed with the main structure, without secondary bonding with adhesive, and the product has better pressure resistance.

[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0115] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for manufacturing a hemispherical cover based on a winding process, characterized in that, It comprises the following steps: S1, winding core preparation: First, install the metal core mold on the winding machine, then wrap the sealing layer on the surface of the metal core mold, and then set the winding program of the winding machine; S2, carbon fiber inner layer preparation: S2.1, carbon fiber inner layer winding: first, evenly brush a layer of winding resin on the surface of the heat insulation layer, the first layer of spiral winding ensures that there is no opening end overcut winding, no hole expansion, and the shaft end ensures that the carbon fiber yarn is hung on the metal core mold, then use carbon cloth impregnated with resin to reinforce the opening end, and the reinforcing area is reduced by 50-80mm wide from the plane outer diameter; The second layer of spiral winding ensures that there is no opening end to expand the hole with the plane outer diameter as the opening diameter, and the center of the expanded hole area is filled and reinforced with fiberglass cloth impregnated with resin; Repeat the above second layer spiral winding process four times, check the flatness of the product, and use carbon cloth to fill and smooth the defect position after pre-curing; S3, intermediate layer installation; The intermediate layer includes a foam layer, a reinforcing layer and a fiberglass plate layer, which are installed on the carbon fiber inner layer in sequence; S4, carbon fiber outer layer preparation: S4.1, carbon fiber outer layer winding: first, brush a layer of winding resin on the fiberglass plate, the first layer of spiral winding requires no opening end overcut winding, no hole expansion, and the shaft end ensures that the carbon fiber yarn is hung on the metal core mold; Use fiberglass cloth impregnated with resin to reinforce the opening end, and the reinforcing area is reduced by 50-80mm wide from the plane outer diameter; The second layer of spiral winding ensures that there is no opening end to expand the hole with the plane outer diameter as the opening diameter, and the center of the expanded hole area is filled and reinforced with fiberglass cloth impregnated with resin; Repeat the above second layer spiral winding process two times, check the flatness of the product, and use carbon cloth to fill and smooth the defect position after pre-curing; After laying two layers of carbon cloth on the entire outside of the product, solidify it; S5, post-processing.

2. The method of claim 1, wherein the method further comprises: In S1, the installation of the metal core mold specifically includes the following steps: First, use the derrick to flip the metal core mold horizontally and fix it on the mold tool, use the derrick to lift the mold tool to the winding machine, then manually assist the single shaft to be inserted on one side of the winding machine drive shaft and clamped, and use screws to tighten and fix; The sealing layer specifically includes the following steps: After cleaning the surface of the metal core mold with ethyl acetate, lay a layer of polytetrafluoroethylene release cloth, then lay 2-3mm thick rubber inside the product cutting line, overlap the position, polish and process, vacuum bag the entire heat insulation layer surface, and perform pressure exhaust treatment; Setting the winding program specifically includes the following steps: Install the carbon fiber yarn reel on the yarn holder, set the winding tension to 50N / axis, the winding angle to 18°~20°, and debug the little cutting point winding program, and the hole expansion radius to 25~45mm; Start the winding machine, detect the clamping stability during the rotation of the drive shaft, stop winding, and remove the mold tool.

3. The method of claim 2, wherein the method further comprises: The vacuum degree of the vacuum bag is below-80kpa.

4. The method of claim 1, wherein the method further comprises: In S2, the pre-curing specifically includes the following steps: Lay two layers of glue absorbing cloth on the product, then wrap a layer of non-porous isolation film, and use dry yarn to wind a layer of non-opening spiral layer for pressure; The installation lifting tool and the rotating curing tool are transported to the oven and connected with the rotating device of the oven, and then the rotating heating and pre-curing are performed.

5. The method of claim 4, wherein the method further comprises: The pre-curing temperature is 100-120℃, and the time is 6-8h.

6. The method of claim 1, wherein the method further comprises: In S4, the curing specifically includes the following steps: Before curing, two layers of glue absorbing cloth are pasted on the product, and then a layer of non-porous isolation film is wrapped, and a layer of non-opening spiral layer is wound with dry yarn for pressure. The installation lifting tool and the rotating curing tool are transported to the oven and connected with the rotating device of the oven, and then the rotating heating and curing are performed.

7. The method of claim 6, wherein the method further comprises: The curing temperature is 140-160℃, and the time is 6-8h.

8. A method of manufacturing a hemispherical cover based on a winding process according to any one of claims 4-6, characterized in that, The rotating speed of the pre-curing and curing is 5-10r / min, and the temperature rising and falling speed is not greater than 2℃ / min.

9. The method of claim 1, wherein the method further comprises: In S2 and S4, the winding resin is epoxy resin, and the ratio of epoxy resin to curing agent is 3:

1.

10. The method of claim 1, wherein the method further comprises: In S5, the post-processing includes cutting demolding and machining.

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