Integral tandem type composite material hollow framework forming method

Abstract

The invention belongs to the technical field of composite material part processing, and discloses an integral tandem type composite material hollow framework forming method which comprises the steps of mold design and manufacturing, sample piece design and manufacturing, manufacturing of an air bag through a mold and a sample piece, and laying of a composite material cloth layer in the mold. Placing an air bag in the laid composite material cloth layer, wrapping the composite material cloth layer, wrapping the air bag with the composite material cloth layer, pre-closing and closing the mold, providing a vacuum environment and a thermocuring environment for the closed mold, opening the mold, firstly taking out the air bag, and then taking out the product; wherein the air bag is a silica gel bag made of silica gel, and a supporting column is arranged in the silica gel bag. The silicon capsule serves as a laying mold and a pressure transmitting medium, the product laying process is facilitated, the operation process is simplified, and operability is improved; the supporting structure is additionally arranged in the air bag, the supporting structure is connected with the bag body on one side and separated from the bag body on the other side, the effect of enhancing the rigidity of the silicon capsule can be achieved through the structure, and the effect that the silicon capsule serves as a laying mold in the product laying process is achieved; according to the air bag structure with the fracture, the tandem type integral air bag can be pulled out as original after a product is manufactured, and the effects of repeated use and cost reduction can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material parts processing, and relates to a processing method of an integral serial composite material, and in particular to a forming method of an integral serial composite material hollow skeleton. Background Art

[0002] The integral serial hollow frame is a typical frame structure, which can achieve the best cost-effectiveness between structural rigidity and weight. Under the condition of achieving structural rigidity, the integral serial structure avoids the connection area, connection area reinforcement and standard parts, which can greatly reduce the structural weight. It is the optimal solution for the design of serial frame structure.

[0003] In order to meet the structural assembly requirements, the overall serial composite hollow skeleton structure generally includes a serial overall structure, a "convex"-shaped cross-sectional structure, a semi-"convex"-shaped cross-sectional structure, a "C"-shaped cross-sectional structure, a "J"-shaped cross-sectional structure, etc., which are difficult to manufacture; the traditional serial hollow skeleton chooses to divide the serial skeleton into two front / rear skeletons and multiple skeleton connectors, and assemble the front / rear skeleton and the skeleton connectors by riveting to reduce the manufacturing difficulty; or the overall hollow skeleton structure is split into two "C"-shaped structures and then assembled by gluing to reduce the manufacturing difficulty.

[0004] The serial skeleton structure is divided into at least five parts, namely the front / rear skeleton, the upper connecting parts, the inner / outer connecting parts, and the middle connecting parts. The connection areas of the five parts need to be designed and strengthened, and the five parts are riveted and assembled with rivets, which results in a large sacrifice in product weight. The five products are riveted and assembled, and assembly tooling needs to be manufactured for assembly positioning, which places higher demands on assembly tooling. The rigidity of individual parts becomes weaker, the deformation of parts becomes larger, and the assembly is more difficult.

[0005] The overall hollow skeleton structure is split into two "C"-shaped structures and then assembled by gluing. The connection area needs to be designed and strengthened, resulting in a large sacrifice in product weight. To assemble two products, assembly tooling needs to be manufactured for assembly positioning, which places higher demands on assembly tooling. The rigidity of individual parts becomes weaker, the deformation of parts becomes larger, the assembly is more difficult, and the final shape accuracy of the product is low.

[0006] Therefore, it is currently required that the overall hollow skeleton structure cannot be disassembled and must be processed as a whole, so a new process method is needed. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for forming an integral tandem composite hollow skeleton, which can improve the forming quality of the integral tandem composite hollow skeleton and reduce the manufacturing cost.

[0008] The technical solution of the present invention is as follows:

[0009] A method for forming an integral tandem composite hollow skeleton comprises the following steps:

[0010] S1, mold design and manufacturing;

[0011] S2, prototype design and manufacturing;

[0012] S3, manufacturing the airbag using the mold and the sample;

[0013] S4, laying out the composite material layers in the mold;

[0014] S5, placing an airbag in the laminated composite material fabric layer;

[0015] S6, re-wrapping the composite material cloth layer to wrap the airbag with the composite material cloth layer;

[0016] S7, performing pre-molding and mold closing of the mold;

[0017] S8, providing a vacuum environment and a heat curing environment for the mold after mold closing;

[0018] S9, open the mold, take out the airbag first, and then take out the product;

[0019] The airbag is a silicone capsule made of silica gel, and a supporting column is arranged inside the silicone capsule.

[0020] Furthermore, the airbag in S3 is manufactured by paving uncured silicone sheets or raw silicone sheets, and the total paving thickness is 4.5-6 mm.

[0021] Furthermore, the steps of S3 include:

[0022] S31, placing the sample in the lower mold of the mold;

[0023] S32, lay the silicone sheet on the sample layer by layer, and vacuumize each layer of silicone sheet; when laying, reserve the air inlet of the airbag;

[0024] S33, adding a supporting column in the weak rigidity area, wherein the supporting column is a column formed by curling a silicone sheet.

[0025] Furthermore, in S33, the lower side of the support column is connected to the laid silicone sheet, and the upper side of the support column is isolated from the laid silicone sheet by an insulator.

[0026] Furthermore, the airbag is an airbag with a fracture, specifically: in the manufacturing step S32 of the airbag, an unconnected fracture of the silicone sheet is reserved, and the fracture is set at the outermost boundary position of the corresponding composite hollow skeleton; the unconnected fractures are separated by an isolation plate after demolding treatment.

[0027] Furthermore, in S5, when the airbag with a fracture is used, the fracture is subjected to pressure equalization:

[0028] The fracture of the airbag is covered with an isolation film; an uncured silicone sheet is placed in the middle gap of the fracture to fill it and covered with an isolation film; finally, a local pressure equalizing plate is placed at the fracture.

[0029] Furthermore, in S4, after the composite material cloth layer is laid, a layer of polyvinyl fluoride film is laid to isolate the airbag; in S5, talcum powder is applied between the airbag and the polyvinyl fluoride film.

[0030] Furthermore, in S6, the overlapping positions of the back-wrapping cloth layers are staggered to avoid local excessive thickness; and the overlapping size of the back-wrapping cloth is 15 to 25 mm.

[0031] Furthermore, it also includes manufacturing the prefabricated sheet and using the prefabricated sheet:

[0032] Manufacturing prefabricated sheets: using the same system of materials as the composite hollow skeleton to manufacture prefabricated sheets, the number of layers of the prefabricated sheets is 1 to 2;

[0033] Use preform: In the mold closing of S7, the preform is placed at the mold closing position of the mold and remains on the surface of the hollow skeleton of the composite material after molding.

[0034] The beneficial effects of the present invention are as follows:

[0035] (1) The silicon capsule of the present invention serves as both a laying mold and a pressure transmission medium, which facilitates the product laying process, simplifies the operation process, and improves operability;

[0036] (2) The R corner of the silicone capsule of the present invention is ductile, and the R corner of the product can be compacted and evenly pressed during the curing process, and the quality of the R corner of the product is better than that of the vacuum bag method;

[0037] (3) The curing pressure source of the composite material of the present invention is the positive pressure of the autoclave, which has low requirements on the rigidity of the overall structure of the tooling, and the tooling structure can be designed as a simple, lightweight thin-shell tooling;

[0038] (4) When the size of the silicon capsule of the present invention is designed, a compensation gap is reserved between the silicon capsule and the inner surface of the product. At the same time, the thin shell structure tooling is easy to operate and does not cause cloth clamping defects;

[0039] (5) The present invention adds a support structure to the airbag, which is connected to the bladder body on one side and separated from the bladder body on the other side. This structure can enhance the rigidity of the silicon capsule and enable the silicon capsule to function as a laying mold during the product laying process;

[0040] (6) The airbag structure with a fracture proposed in the present invention can realize the in-line integral airbag to be deployed as it is after the product is manufactured, so as to achieve the effect of repeated use and reduce costs;

[0041] (7) The silicon capsule of the present invention does not need to be filled with sand and is light in weight, so it can realize the manufacture and use of large-sized silicon capsules. The design can realize the manufacture of large-scale serial composite hollow skeleton products. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solution of the implementation method of the patent of the present invention, the following is a brief introduction to the drawings required for use in the implementation method. It should be understood that the following drawings only show certain embodiments of the patent of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 The figure is a diagram of the integral tandem composite hollow skeleton structure processed by the present invention;

[0044] Figure 2 It is a diagram of the structure of the integral serial silicon capsule with a fracture of the present invention;

[0045] Figure 3 It is a diagram of the splicing structure of two individually enclosed silicon capsules in an embodiment of the present invention;

[0046] Figure 4 This is a structural diagram of a silicon capsule with an additional support structure and local thickening in an embodiment of the present invention;

[0047] Figure 5 The figure is a method for manufacturing the fracture of a silicon capsule according to an embodiment of the present invention;

[0048] Figure 6 The figure is a diagram of the fracture splicing and pressure equalization method of the silicon capsule of the present invention;

[0049] Among them, 1 is an isolation membrane or Tedlar film, 2 is an array support column structure, 3 is a conventional raw silicone sheet layer, 4 is a raw silicone sheet layer wrapped back at the fracture, 5 is a demoulding cloth, 6 is an isolation plate, 7 is a fracture splicing structure silicone capsule 1, 8 is a fracture splicing structure silicone capsule 2, 9 is a Tedlar film, 10 is a silicone gel (silicone or raw silicone sheet) filled at the splicing, and 11 is a pressure-equalizing gasket. DETAILED DESCRIPTION

[0050] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships as given in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a mechanical connection or a point connection; it can be a direct connection or a connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0053] Embodiment 1:

[0054] A method for forming an integral tandem composite hollow skeleton comprises the following steps:

[0055] S1, mold design and manufacturing;

[0056] S2, prototype design and manufacturing;

[0057] S3, manufacturing the airbag using the mold and the sample;

[0058] S4, laying out the composite material layers in the mold;

[0059] S5, placing an airbag in the laminated composite material fabric layer;

[0060] S6, re-wrapping the composite material cloth layer to wrap the airbag with the composite material cloth layer;

[0061] S7, performing pre-molding and mold closing of the mold;

[0062] S8, providing a vacuum environment and a heat curing environment for the mold after mold closing;

[0063] S9, open the mold, take out the airbag first, and then take out the product;

[0064] The airbag is a silicone capsule made of silica gel, and a supporting column is arranged inside the silicone capsule.

[0065] The airbag in S3 is made of uncured silicone sheets or raw silicone sheets, with a total paving thickness of 4.5-6mm.

[0066] The steps of S3 include:

[0067] S31, placing the sample in the lower mold of the mold;

[0068] S32, lay the silicone sheet on the sample layer by layer, and vacuumize each layer of silicone sheet; when laying, reserve the air inlet of the airbag;

[0069] S33, adding a supporting column in the weak rigidity area, wherein the supporting column is a column formed by curling a silicone sheet.

[0070] In S33, the lower side of the support column is connected to the laid silicone sheet, and the upper side of the support column is isolated from the silicone sheet laid on the upper side by an insulator.

[0071] The airbag is an airbag with a fracture, specifically: in the manufacturing step S32 of the airbag, an unconnected fracture of the silicone sheet is reserved, and the fracture is set at the outermost boundary position of the corresponding composite hollow skeleton; the unconnected fractures are separated by an isolation plate after demolding treatment.

[0072] In S5, when the airbag with a break is used, the break is subjected to pressure equalization:

[0073] The fracture of the airbag is covered with an isolation film; an uncured silicone sheet is placed in the middle gap of the fracture to fill it and covered with an isolation film; finally, a local pressure equalizing plate is placed at the fracture.

[0074] In S4, after the composite material cloth layer is laid, a layer of polyvinyl fluoride film is laid to isolate the airbag; in S5, talcum powder is applied between the airbag and the polyvinyl fluoride film.

[0075] In S6, the overlapping positions of the back wrapping cloth layers are staggered to avoid local excessive thickness; the overlapping size of the back wrapping cloth is 15 to 25 mm.

[0076] It also includes the manufacture of prefabricated sheets and the use of prefabricated sheets:

[0077] Manufacturing prefabricated sheets: using the same system of materials as the composite hollow skeleton to manufacture prefabricated sheets, the number of layers of the prefabricated sheets is 1 to 2;

[0078] Use preform: In the mold closing of S7, the preform is placed at the mold closing position of the mold and remains on the surface of the hollow skeleton of the composite material after molding.

[0079] Embodiment 2:

[0080] The main technical concepts adopted in the present invention are:

[0081] (1) In terms of molding principle, the principle of composite material "mother-child bag" is applied, and the "child bag" material in the mother-child bag is upgraded from a vacuum bag to a silicone capsule. The sealing between the "child bag" and the "mother bag" is optimized so that the "child bag" and the "mother bag" are sealed with the mold respectively. The silicone capsule of the "child bag" is sealed with the mold through a more suitable vent nozzle, and the "mother bag" is sealed with the mold using a putty strip.

[0082] (2) Silicone capsules with large cross-sections are used to increase the thickness of the silicone capsules and to increase the local support structure to enhance rigidity, so that the silicone capsules can serve as both a laying mold during the product laying process and a pressure transmission medium during the curing process.

[0083] (3) The silicon capsule can be designed as an integral tandem structure;

[0084] (4) The overall serial structure can add local incisions to achieve the reusability of the silicon capsule;

[0085] (5) The silicon capsule can be designed as a splicing structure to achieve the reusability of the silicon capsule.

[0086] (6) Based on the “mother-child bag” molding principle, the pressure of the inner bag and the outer bag is provided by the autoclave, and the pressure is uniform. The molding mold of the overall serial composite hollow skeleton is designed as a lightweight thin shell structure.

[0087] It should be noted that in the implementation case, those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutations and combinations, so the present invention will no longer describe the technical solutions after the permutations and combinations one by one, but it should be understood that the technical solutions after the permutations and combinations have been disclosed by the present invention. The above is only a preferred example of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0088] (3) Specific implementation steps of the present invention

[0089] Step 1: Tooling design;

[0090] For easy operation, the tooling is designed as a lightweight thin shell structure. The following points should also be noted:

[0091] (1) Reasonable division of tooling;

[0092] (2) The upper and lower parting surfaces are selected close to the R corner;

[0093] (iii) Avoid closed angles;

[0094] (iv) Each side mold to be disassembled shall be designed with a mold opening or mold opening device;

[0095] (5) The plane is used as the upper die surface, and the step surface is used as the lower die surface;

[0096] (6) The hanging should be set according to the weight of the disassembled mold part, and the hanging position should be reasonable;

[0097] (VII) Conduct stiffness simulation analysis;

[0098] (8) A mold guide device is provided, and the mold guide is reasonable;

[0099] (IX) It can achieve sealing, and a leak-proof block is designed on the back of the main mold assembly position;

[0100] (10) The air port of the silicone capsule matches the opening of the mold;

[0101] (XI) The tooling is made of Invar steel, or the heat shrinkage ratio is considered

[0102] Step 2: Tooling manufacturing;

[0103] After the tooling is manufactured, the following points should be noted:

[0104] (I) Checking the machining accuracy of tooling

[0105] (ii) Conduct airtightness inspection

[0106] Step 3: Sample design (on demand, no sample is needed when there is a special molding mold for silicone capsules);

[0107] (1) The sample material may be made of high temperature resistant composite materials or other high temperature resistant materials;

[0108] (ii) Design the sample thickness to be 1.5 times the product thickness;

[0109] (iii) Calculate the number of layers based on the thickness of a single layer of material;

[0110] (iv) Butt joint is adopted for ply laying;

[0111] (5) Symmetrical design of ply;

[0112] (6) Manufactured by vacuum bag-autoclave method;

[0113] (VII) Manufactured using a molding die;

[0114] (VIII) The sample and mold boundaries are consistent

[0115] Step 4: Sample manufacturing (on demand, no sample is needed when there is a special molding mold for silicone capsules);

[0116] (a) The sample laying process adopts the butt-jointing method;

[0117] (ii) Select curing parameters that match the material

[0118] (3) The sample is processed to be flush with the mold position of the tooling mold body or within 0.2mm below the mold surface;

[0119] (iv) Grind the areas that are too thick and thicken the areas that are too thin;

[0120] (V) Grind the R angle until it is consistent with the inner R angle of the product;

[0121] (6) The sample is divided into blocks at parallel positions to ensure that there is no stress between the molding die;

[0122] Step 5: Airbag Manufacturing

[0123] (I) Silicon capsules can be in three forms:

[0124] 1) Integral serial silicon capsule;

[0125] The overall serial structure is consistent with the product, and the cross-section is a closed structure. Except for the gas outlet, the rest of the overall serial silicon capsule is a closed structure. Figure 2 ;

[0126] 2) Silicon capsule with fracture;

[0127] Only one side of the most closed structure is left as a continuous structure, and each of the remaining closed structures is set with a fracture, and the fracture is closed. Figure 3 , making the silicon capsule reusable;

[0128] 3) Two silicon capsules are spliced ​​together;

[0129] Disconnect all closed structures and use two silicone capsules that are each sealed with silicone to splice them together. Figure 4 , and the silicon capsule can be reused;

[0130] (ii) Silicone capsule materials shall be 1453 uncured silicone sheets or other raw silicone sheets with similar properties and other materials;

[0131] (III) The thickness of the raw silicone sheet is 3 to 4 layers (single layer is 1.5 mm, other thickness silicone sheets need to be converted into layers) or silicone support points are added to ensure a certain rigidity;

[0132] Pay special attention to the thickness of the silicone sheet. When the product cavity size is ≤50mm, 3 layers of silicone sheets can be laid directly; when the product cavity size is >50mm, 4 layers of silicone sheets can be laid. Figure 5 ; The thickness of the silicone should not be too thick, which is not conducive to the pressure transmission during the curing process;

[0133] (iv) Vacuum each layer of silicone sheet;

[0134] Vacuuming parameters are: vacuum - 0.07MPa, time not less than 15min;

[0135] (V) In the area where the rigidity is still weak, add silicone support points. The support points are columns with a diameter of 10 to 20 mm or rectangular blocks with a side length of 10 to 20 mm. A layer of demoulding membrane (or other materials with good isolation effect) is laid on the upper side of the support points to isolate the support points from the upper silicone capsules, and the lower side of the support points is connected to the silicone capsules. Figure 5 ;

[0136] (VI) Silicone capsule with fracture and two silicone capsules spliced ​​together. For two types of silicone capsules, an isolation plate should be placed at the fracture. The thickness of the isolation plate is about 0.5-1 mm and the material is composite material or metal. The surface of the isolation plate is subjected to demoulding treatment (brushing release agent, pasting release cloth or using isolation film for isolation). Raw silicone sheets are used on both sides of the isolation plate to seal the end faces of the capsule. Figure 6 ;

[0137] (VII) The silicon capsule is a hollow capsule with silicone support points set locally, and does not need to be filled with sand or other materials;

[0138] Special attention should be paid to the fact that not filling the silicon capsule with sand can effectively reduce the weight of the silicon capsule and enhance the portability of the silicon capsule.

[0139] Step 6: Prefabricated film manufacturing (on demand)

[0140] (1) Use glass fiber prepreg with the same resin system as the product to make prefabricated sheets, with 1 to 2 layers and a thickness generally not exceeding 0.3 mm;

[0141] (ii) The prefabricated sheet is a gasket placed on the mold clamping position of the tooling after the product is laid. It can remain on the surface of the product after the product is formed. If an isolation film is added between the prefabricated sheet and the layup, the prefabricated sheet can be removed after the product is formed.

[0142] Step 7: Lay Up

[0143] (i) The layers must be laid, compacted, and rolled without bridging or wrinkles; they must be spliced ​​as required; and a back-wrapping layer must be left out, with good isolation between the back-wrapping layers;

[0144] (ii) Vacuum after laying the first layer, and then vacuum every 3 to 4 layers;

[0145] (III) After all the layers are laid before backpacking, a layer of polyvinyl fluoride film is laid to isolate the silicone capsule and facilitate mold opening;

[0146] Step 7: Place the Silicon Capsule

[0147] (i) Place the silicon capsule in the ply and the air inlet nozzle in the opening coordinated with the tooling;

[0148] Pay special attention to check the accuracy of the silicone capsule placement, and avoid problems such as bridging and stress;

[0149] (ii) Apply talcum powder between the silicone capsule and the polyvinyl fluoride film (such as CZ-PVF-25) (as needed); talcum powder helps demoulding, but special attention should be paid to protecting the ply when applying talcum powder to prevent talcum powder from entering the prepreg;

[0150] (III) When using a silicone capsule with a fracture or two silicone capsules spliced ​​together, due to the general shrinkage of silicone capsules, it is necessary to perform pressure equalization at the fracture or splicing of the silicone. The pressure equalization method is as follows:

[0151] Use polyvinyl fluoride film (or release cloth, isolation film) to cover the fracture; place uncured silicone sheet (or silicone with similar performance to RTV1556 and other materials with similar performance) to fill the gap in the middle of the fracture or splicing, and use polyvinyl fluoride film (or release cloth, isolation film) to cover it;

[0152] Place a local pressure plate (0.2mm to 0.3mm thick prepreg) at the joint;

[0153] Step 8: Backpacking the fabric layer

[0154] (1) The overlapping positions of each back-wrapping cloth layer are staggered to avoid excessive thickness in some areas;

[0155] (ii) The overlap size of the back package is 15 to 25 mm;

[0156] (3) Avoid over-tightening the back-wrapped fabric layer; over-tightening will result in greater resistance to the fabric layer sliding layer by layer during the curing process, which may lead to delamination and gap out-of-tolerance faults;

[0157] Step 9: Pre-molding

[0158] (1) Pre-close the mold and use guide pins to ensure the accuracy of mold closing. The mold closing gap should be ≤0.2mm;

[0159] (2) Pre-mold closing to confirm whether the mold can be closed smoothly;

[0160] (iii) After pre-closing, open the mold again and process the defective fabric layer;

[0161] Step 10: Place prefab (as needed)

[0162] (i) The length of a single prefabricated sheet should not be too long, ≤150mm, or a 1mm vent hole should be punched; the width of a single side of the prefabricated sheet should not be greater than 15mm;

[0163] (ii) The prefabricated pieces should be butt-jointed with a gap of 0 to 2 mm; overlapping is not allowed;

[0164] Step 11: Mold Closing

[0165] (1) Perform mold closing according to the pre-mold closing method;

[0166] (2) Control the mold clearance ≤ 0.2mm;

[0167] Step 12: Make a vacuum bag

[0168] (1) The vacuum bag is not bridged or sealed;

[0169] (2) The number and location of vacuum nozzles meet the requirements of vacuum extraction and vacuum testing;

[0170] Step 13: Vacuum test

[0171] After the vacuum bag is pasted, check the vacuum degree

[0172] Step 14: Curing

[0173] (a) Curing using an autoclave;

[0174] (ii) Determine the curing parameters according to the materials used;

[0175] Step 15: Open the mold

[0176] (1) Remove the tooling cover plate, side molds, etc. from the main mold body;

[0177] (2) Taking the product out of the main mold;

[0178] (3) Remove the silicon capsule from the product;

[0179] Special note: When using a whole silicone capsule without fractures, the silicone capsule needs to be destroyed to be taken out; when using a whole silicone capsule with fractures or a spliced ​​silicone capsule, the silicone capsule can be taken out gradually and the silicone capsule can be reused.

[0180] Embodiment 3:

[0181] constitute:

[0182] (I) Forming principle

[0183] In terms of molding principle, the "mother-child bag" principle of composite materials is applied, and the "child bag" material in the mother-child bag is upgraded from a vacuum bag to a silicone capsule. The sealing between the "child bag" and the "mother bag" is optimized so that the "child bag" and the "mother bag" are sealed with the mold respectively. The "child bag" silicone capsule is sealed with the mold through a more suitable ventilation nozzle, and the "mother bag" is sealed with the mold using putty strips.

[0184] (II) Tooling structure

[0185] A thin shell tooling is used, and the tooling is provided with an air port that matches the integral serial silicon capsule.

[0186] (III) Integral tandem silicon capsule

[0187] The silicon capsule is designed as an integral serial structure and is a disposable consumable structure silicon capsule.

[0188] (IV) Integral serial silicon capsule with fracture

[0189] The silicon capsule is designed as an integral serial structure with a fracture, and due to the fracture, the silicon capsule can be reused.

[0190] (V) Serial silicon capsule with splicing structure

[0191] The silicon capsule is designed as a splicing structure, and due to the splicing form, the silicon capsule can be reused.

[0192] (VI) Silicon capsule structure strengthening method

[0193] 1) Increase the thickness of local silicone sheet layer;

[0194] 2) Apply slight positive pressure when laying the layers.

[0195] (VII) Silicon capsule fracture manufacturing method

[0196] Use an isolation plate wrapped with a demoulding cloth to isolate the silicone capsules on both sides of the fracture; lay the raw silicone sheet back on the fracture to ensure the sealing of the silicone capsule at the fracture;

[0197] (VIII) Methods for splicing and equalizing pressure of silicon capsule fractures during product manufacturing

[0198] Use polyvinyl fluoride film (or release cloth, isolation film) to cover the fracture; place uncured silicone sheet (or silicone with similar performance to RTV1556 and other materials with similar performance) to fill the gap in the middle of the fracture or splicing, and use polyvinyl fluoride film (or release cloth, isolation film) to cover it;

[0199] Place a local pressure plate (0.2mm to 0.3mm thick prepreg) at the joint.

[0200] (IX) Apply talcum powder between the silicone capsule and the polyvinyl fluoride film (such as CZ-PVF-25);

[0201] Talc helps demoulding, but special attention should be paid to protecting the ply when applying talc to prevent talc from entering the prepreg.

[0202] Implementation steps:

[0203] Step 1: Tooling design;

[0204] For easy operation, the tooling is designed as a lightweight thin shell structure.

[0205] Step 2: Tooling manufacturing;

[0206] After the tooling is manufactured, attention should be paid to testing the tooling processing accuracy and conducting an airtightness check. Step 3: Sample design (on demand, no sample is required when there is a special molding mold for silicone capsules);

[0207] Step 4: Sample manufacturing (on demand, no sample is needed when there is a special molding mold for silicone capsules);

[0208] Step 5: Airbag Manufacturing

[0209] The silicon capsule can be in three forms: an integral serial silicon capsule; a silicon capsule with a break; two silicon capsules spliced ​​together;

[0210] Step 6: Prefabricated film manufacturing (on demand)

[0211] Step 7: Lay Up

[0212] The layers should be laid, compacted and rolled without bridging or wrinkles; and spliced ​​as required; and a back-wrapping layer should be left out, with good isolation between the back-wrapping layers;

[0213] Step 7: Place the Silicon Capsule

[0214] The silicon capsule is placed in the layup and the air inlet nozzle is positioned in the opening coordinated with the tooling;

[0215] Step 8: Backpacking the fabric layer

[0216] The overlap positions of each back-wrapped cloth layer are staggered to avoid local excessive thickness; the overlap size of the back-wrapped cloth layer is 15-25mm; the back-wrapped cloth layer should not be too tight; too tight will lead to large resistance to the sliding of the cloth layer by layer during the curing process, which is prone to delamination and gap out-of-tolerance faults;

[0217] Step 9: Pre-molding

[0218] Pre-close the mold and use guide pins to ensure the accuracy of mold closing. The mold-to-mold clearance should be ≤0.2mm.

[0219] Step 10: Place prefab (as needed)

[0220] Step 11: Mold Closing

[0221] Control the mold clearance ≤0.2mm;

[0222] Step 12: Make a vacuum bag

[0223] Step 13: Vacuum test

[0224] After the vacuum bag is pasted, check the vacuum degree

[0225] Step 14: Curing

[0226] Use autoclave for curing;

[0227] Step 15: Open the mold

[0228] Remove the tooling upper cover plate, side molds, etc. from the main mold; take the product out of the main mold; take the silicone capsule out of the product.

Claims

1. A method for forming an integral tandem composite hollow skeleton, characterized in that: The following steps are involved: S1, mold design and manufacturing; S2, prototype design and manufacturing; S3, manufacturing the airbag using the mold and the sample; S4, laying out the composite material layers in the mold; S5, placing an airbag in the laminated composite material fabric layer; S6, re-wrapping the composite material cloth layer to wrap the airbag with the composite material cloth layer; S7, performing pre-molding and mold closing of the mold; S8, providing a vacuum environment and a heat curing environment for the mold after mold closing; S9, open the mold, take out the airbag first, and then take out the product; The airbag is a silicone capsule made of silica gel, and a supporting column is arranged inside the silicone capsule.

2. The method for forming an integral tandem composite hollow skeleton according to claim 1, characterized in that: The airbag in S3 is made of uncured silicone sheets or raw silicone sheets, with a total paving thickness of 4.5-6mm.

3. The method for forming an integral tandem composite hollow skeleton according to claim 2, characterized in that: The steps of S3 include: S31, placing the sample in the lower mold of the mold; S32, lay the silicone sheet on the sample layer by layer, and vacuumize each layer of silicone sheet; when laying, reserve the air inlet of the airbag; S33, adding a supporting column in the weak rigidity area, wherein the supporting column is a column formed by curling a silicone sheet.

4. The method for forming an integral tandem composite hollow skeleton according to claim 3, characterized in that: In S33, the lower side of the support column is connected to the laid silicone sheet, and the upper side of the support column is isolated from the silicone sheet laid on the upper side by an insulator.

5. The method for forming an integral tandem composite hollow skeleton according to claim 3, characterized in that: The airbag is an airbag with a fracture, specifically: in the manufacturing step S32 of the airbag, an unconnected fracture of the silicone sheet is reserved, and the fracture is set at the outermost boundary position of the corresponding composite hollow skeleton; the unconnected fractures are separated by an isolation plate after demolding treatment.

6. The method for forming an integral tandem composite hollow skeleton according to claim 5, characterized in that: In S5, when the airbag with a break is used, the break is subjected to pressure equalization: The fracture of the airbag is covered with an isolation film; an uncured silicone sheet is placed in the middle gap of the fracture to fill it and covered with an isolation film; finally, a local pressure equalizing plate is placed at the fracture.

7. The method for forming an integral tandem composite hollow skeleton according to claim 1, characterized in that: In S4, after the composite material cloth layer is laid, a layer of polyvinyl fluoride film is laid to isolate the airbag; in S5, talcum powder is applied between the airbag and the polyvinyl fluoride film.

8. The method for forming an integral tandem composite hollow skeleton according to claim 1, characterized in that: In S6, the overlapping positions of the back wrapping cloth layers are staggered to avoid local excessive thickness; the overlapping size of the back wrapping cloth is 15 to 25 mm.

9. The method for forming an integral tandem composite hollow skeleton according to claim 1, characterized in that: It also includes the manufacture of prefabricated sheets and the use of prefabricated sheets: Manufacturing prefabricated sheets: using the same system of materials as the composite hollow skeleton to manufacture prefabricated sheets, the number of layers of the prefabricated sheets is 1 to 2; Use preform: In the mold closing of S7, the preform is placed at the mold closing position of the mold and remains on the surface of the hollow skeleton of the composite material after molding.

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