Forming die and integral forming method for wingtip of variable-thickness cavity foam sandwich structure

Abstract

The embodiment of the invention provides a forming die of a variable-thickness cavity foam sandwich structure wingtip. The forming die comprises an upper die, a lower die, a side die, a combined core die and an occupied core die. The combined core mold is placed between the upper mold and the lower mold and comprises a glass fiber plate and a metal core mold, and the glass fiber plate and the metal core mold are connected through a pressure-sensitive adhesive tape; the side die is placed between the upper die and the lower die, located on the side edge of the combined core die and used for providing lateral pressure for a product and guaranteeing the internal quality of the side face of the product. The occupied core molds are placed between the upper mold and the lower mold, located on the two sides of the combined core mold and used for forming a cavity, a lightening hole and a connecting hole in a product, and the occupied core molds are metal occupied blocks. Compared with the prior art, the forming die is used for forming the variable-thickness cavity foam sandwich structure wingtip, the forming difficulty is low, the forming process is simple, the cost is low, and the inner quality of the obtained variable-thickness cavity foam sandwich structure wingtip is good.

Description

Technical Field

[0001] The present application relates to the technical field of carbon fiber production and molding, and in particular to a molding die and an integrated molding method for a wing tip of a variable thickness cavity foam sandwich structure. Background Art

[0002] The wingtip is an important component of an aircraft wing. It is used to block the vortex formed by the wing when the aircraft takes off and reduce the resistance encountered by the aircraft.

[0003] In order to achieve faster speeds and longer flight time, weight reduction has always been a top priority in the development of aircraft. In order to achieve the weight reduction goal, a large amount of carbon fiber composite materials will be used in the fuselage structure. In addition, the structure of each component is lightened: for example, adding lightening holes and using low-density sandwich materials are all common methods in weight reduction design.

[0004] In the prior art, the wing tip is usually integrally formed using a foam sandwich structure to increase the rigidity of the part, and then a special-shaped cavity structure is added to the structure. This greatly increases the difficulty of forming, and the forming process of this method is cumbersome, the cost is high, and the internal quality of the obtained part is also poor.

[0005] Therefore, the embodiments of the present application provide a molding die and a molding method to solve the above problems. Summary of the invention

[0006] An embodiment of the present application provides a molding mold for a wing tip of a variable thickness cavity foam sandwich structure. Using the molding mold to mold the wing tip of a variable thickness cavity foam sandwich structure not only has low molding difficulty, simpler molding process, and lower cost, but also the obtained variable thickness cavity foam sandwich structure wing tip has better internal quality.

[0007] The embodiment of the present application provides a molding die for a wing tip of a variable thickness hollow foam sandwich structure, comprising an upper die, a lower die, a side die, a combined core die and a placeholder core die;

[0008] The combined core mold is placed between the upper mold and the lower mold, wherein the combined core mold includes a glass fiber board and a metal core mold, and the glass fiber board and the metal core mold are connected by a pressure-sensitive tape;

[0009] The side mold is placed between the upper mold and the lower mold and is located on the side of the combined core mold, and is used to provide lateral pressure on the product to ensure the internal quality of the product side;

[0010] The placeholder core mold is placed between the upper mold and the lower mold and located on both sides of the combined core mold, and is used to form cavities, lightening holes and connecting holes on the molded product, wherein the placeholder core mold is a metal placeholder block.

[0011] In the molding die of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, a core mold stopper is also included;

[0012] The core mold stopper is placed between the upper mold and the lower mold and is located on the side of the combined core mold, and is used to fix and compact the combined core mold.

[0013] The molding mold of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application also includes a demolding tool, which is used to demold the combined core mold and the placeholder core mold after the product is formed to ensure smooth demolding without damaging the product.

[0014] In the molding mold of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, the area on the upper mold, lower mold, side mold and combined core mold for laying the adhesive release cloth is reserved with a thickness of one layer of release cloth.

[0015] In the molding die of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, a slide groove is provided on the lower mold, and the slide groove is used to facilitate the installation of the side mold on the lower mold;

[0016] The combined core mold is provided with a boss structure, and the side mold is provided with a positioning slot, wherein the boss structure is provided with a threaded hole;

[0017] The metal placeholder block is provided with a positioning guide column, and the side mold is provided with a positioning hole.

[0018] The present application also provides an integrated molding method for a wing tip of a variable thickness cavity foam sandwich structure, which is used in a molding mold for a wing tip of a variable thickness cavity foam sandwich structure described in any of the above embodiments, and the method comprises:

[0019] Lay a layer of demoulding tape on the upper mold, lower mold, side mold and combined core mold respectively;

[0020] Laying the prepreg of the outer skin of the product on the lower mold, and performing pre-extraction after the laying is completed;

[0021] Laying circumferential layers with prepreg on two foams and the combined core mold for forming the foam core area of ​​the product, and pre-drawing after the laying, while placing metal placeholders in the corresponding foams;

[0022] The side mold, the combined core mold and the two foams are installed on the lower mold, and after installation, carbon fiber twisted filaments are filled in the R corner formed by the combined area of ​​the foam and the combined core mold to supplement the mold surface;

[0023] Laying the skin prepreg of the upper part of the product on the combined core mold and the two foams, and installing the core mold stopper on the combined core mold;

[0024] The upper mold is mounted on the lower mold for mold closing, and after the mold closing is completed, it is sent to a hot press for cold pressing and curing. After curing and molding, it is demoulded and processed to prepare a variable thickness cavity foam sandwich structure wing tip.

[0025] In the one-piece molding method of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, the side mold, the combined core mold and the two foams are installed on the lower mold, including:

[0026] Installing the side mold to the corresponding position of the lower mold through the sliding groove on the lower mold;

[0027] The combined core mold is installed on the lower mold through the boss structure on the combined core mold and the positioning slots on the side mold;

[0028] The two foams are mounted on the lower mold through the positioning guide pins on the metal placeholder block and the positioning holes on the side mold.

[0029] In the one-piece molding method of the variable thickness cavity foam sandwich structure wing tip described in the embodiment of the present application, the demoulding and processing are performed after the curing molding to prepare the variable thickness cavity foam sandwich structure wing tip, including:

[0030] After curing and molding, the mold is lifted off the hot press by a forklift;

[0031] Open the upper mold, remove the side molds, and install the demoulding block;

[0032] The combined core mold and the metal placeholder block are taken out by a pin puller, and the product is processed to prepare a wing tip with a variable thickness cavity foam sandwich structure.

[0033] In the one-piece molding method of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, the removing of the combined core mold and the metal placeholder block by a pin puller comprises:

[0034] The metal place-taking block and the metal core mold in the combined core mold are taken out by the pin puller, and then the glass fiber board in the combined core mold is taken out.

[0035] In the one-piece molding method of the variable thickness hollow foam sandwich structure wing tip described in the embodiment of the present application, before laying the hoop layer with prepreg on the two foams and the combined core mold, it also includes:

[0036] A layer of adhesive film is laid on the two foams respectively.

[0037] The forming mold of the variable thickness cavity foam sandwich structure wing tip provided in the embodiment of the present application includes an upper mold, a lower mold, a side mold, a combined core mold and a placeholder core mold; the combined core mold is placed between the upper mold and the lower mold, wherein the combined core mold includes a glass fiber board and a metal core mold, and the glass fiber board and the metal core mold are connected by a pressure-sensitive tape; the side mold is placed between the upper mold and the lower mold, and is located on the side of the combined core mold, and is used to provide lateral pressure on the product to ensure the internal quality of the product side; the placeholder core mold is placed between the upper mold and the lower mold, and is located on both sides of the combined core mold, and is used to form cavities, lightening holes and connecting holes on the product, wherein the placeholder core mold is a metal placeholder block. Compared with the prior art, the use of the forming mold of the embodiment of the present application to form the variable thickness cavity foam sandwich structure wing tip not only has a lower molding difficulty, a simpler molding process, and a lower cost, but also the obtained variable thickness cavity foam sandwich structure wing tip has a better internal quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0039] Figure 1 A top view of the wing tip of the variable thickness hollow foam sandwich structure provided in an embodiment of the present application after molding.

[0040] Figure 2 A side view of the wing tip of the variable thickness hollow foam sandwich structure provided in an embodiment of the present application after molding.

[0041] Figure 3 This is a front view of the upper and lower molds of the molding mold provided in an embodiment of the present application when the molds are closed.

[0042] Figure 4 A side view of the wing tip of the variable thickness hollow foam sandwich structure provided in an embodiment of the present application during demoulding.

[0043] Figure 5 A top view of the combined core mold provided in an embodiment of the present application during positioning.

[0044] Figure 6 A side view of the carbon fiber prepreg provided in an embodiment of the present application during paving.

[0045] Figure 7 A schematic flow chart of a method for integrally molding a wing tip of a variable thickness hollow foam sandwich structure provided in an embodiment of the present application.

[0046] Description of Figure Numbers:

[0047] 2-Product Carbon Fiber Skin 10-Foam Core Area 1 20-Foam Core Area 2

[0048] 30- Product cavity 1 40- Product cavity 2 50- Thickening area

[0049] 60-thinning area 70-upper die 80-lower die

[0050] 90-side mold 100-combination core mold 110-occupying core mold

[0051] 120- core mold block 130- demoulding tooling 140- slide

[0052] 150-threaded hole 160-positioning guide pin 170-carbon fiber prepreg layer

[0053] 180-Carbon fiber twisted filaments 1001-Glass fiber board 1002-Metal core mold DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0055] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0056] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0059] The embodiment of the present application provides a molding die for a wing tip of a variable thickness cavity foam sandwich structure, wherein the specific structure of the wing tip of the variable thickness cavity foam sandwich structure is as follows: Figure 1 and Figure 2 As shown, the variable thickness cavity foam sandwich structure wing tip includes two foam sandwich areas (foam sandwich area 10 and foam sandwich area 20), product carbon fiber skin 2, two cavity areas (product cavity 1 30 and product cavity 2 40), wherein the product cavity 30 is a through cavity and consists of two different thickness areas (thickening area 50 and thinning area 60), the foam and the outside of the cavity are wrapped by a full circle of carbon fiber, and there are carbon fiber ribs between the foam and the cavity. Figures 3 to 6 The molding mold of the variable thickness hollow foam sandwich structure wing tip includes an upper mold 70, a lower mold 80, a side mold 90, a combined core mold 100 and a placeholder core mold 110.

[0060] The upper mold 70 is used to provide pressure on the upper surface of the product, and the upper mold 70 and the lower mold 80 are combined to form the product.

[0061] The combined core mold 100 is placed between the upper mold 70 and the lower mold 80 , wherein the combined core mold 100 includes a glass fiber board 1001 and a metal core mold 1002 , and the glass fiber board 1001 and the metal core mold 1002 are connected by a pressure-sensitive tape.

[0062] Among them, the cavity of this product (variable thickness cavity foam sandwich structure wing tip) is a variable thickness cavity. If you want to form it in one piece, you need to split the core mold in the cavity according to the thickness change, otherwise it cannot be demoulded. Therefore, if Figure 5 The combined core mold is composed of a metal core mold 1002 and a glass fiber board 1001. The surface of the metal core mold 1002 is flat, and the thickness of the glass fiber board 1001 is determined by the thickness difference between the two regions of the product (thickening region 50 and thinning region 60). The glass fiber board 1001 is manufactured according to the thinning region and the glass fiber prepreg of a set thickness pre-pasted on the surface of the combined core mold, and the bag is made and cured, so that the glass fiber board can follow the shape.

[0063] When parts are produced, the prefabricated glass fiber board 1001 is fixed on the metal core mold 1002 with a pressure-sensitive tape, and then the carbon fiber prepreg is laid.

[0064] The side mold 90 is placed between the upper mold 70 and the lower mold 80 and is located on the side of the combined core mold 100 to provide lateral pressure on the product and ensure the internal quality of the product side.

[0065] The placeholder core mold 110 is placed between the upper mold 70 and the lower mold 80 and is located on both sides of the combined core mold 100, and is used to form cavities, lightening holes and connecting holes on the molded product, wherein the placeholder core mold 110 is a metal placeholder block.

[0066] Among them, two foams are needed to form the product, and the two foams are used to generate the foam core area of ​​the product (foam core area 10 and foam core area 20), and the placeholder core mold 110 is placed in the foam, and one placeholder core mold 110 is placed in each foam.

[0067] Among them, attention should be paid to controlling the foam surface during the manufacturing process. The contour of the foam surface should be controlled between ±0.2mm. A larger or smaller surface will cause local underpressure in the product.

[0068] The placeholder core mold 110 is a metal placeholder block, which is positioned by connecting with the lower mold 80 and is used to form structures such as cavities, lightening holes and connecting holes on the molded product.

[0069] In some embodiments, the molding mold of the variable thickness cavity foam sandwich structure wing tip also includes a core mold stopper 120; the core mold stopper 120 is placed between the upper mold 70 and the lower mold 80 and is located on the side of the combined core mold 100 for fixing and compacting the combined core mold 100.

[0070] Among them, the functions of the core mold block 120 are: first, to fix the combined core mold 100 to prevent the combined core mold 100 from warping and deformation during the curing process; second, to compact the combined core mold 100, and compact the two ends when the part is long in the length direction to ensure that the combined core mold 100 presses the prepreg on the lower surface in place during the curing process.

[0071] In some embodiments, the molding mold of the variable thickness cavity foam sandwich structure wing tip also includes a demolding tool 130, which is used to demold the combined core mold 100 and the placeholder core mold 110 after the product is formed to ensure smooth demolding without damaging the product.

[0072] In some embodiments, the areas on the upper mold 70 , the lower mold 80 , the side mold 90 and the combined core mold 100 for laying the adhesive release cloth are reserved with a thickness of one layer of release cloth.

[0073] Among them, since the mold surface needs to be covered with adhesive release cloth to ensure exhaust, a layer of release cloth thickness needs to be reserved on the mold molding surface when designing the mold.

[0074] In some embodiments, a slide groove 140 is provided on the lower mold 80, and the slide groove 140 is used to facilitate the installation of the side mold 90 on the lower mold 80; a boss structure is provided on the combined core mold 100, and a positioning slot is provided on the side mold 90, wherein a threaded hole 150 is provided on the boss structure; a positioning guide column is provided on the metal placeholder block, and a positioning hole is provided on the side mold 90.

[0075] Among them, the side mold 90 is a movable block, which can be moved laterally through the slide groove 140; at the same time, there is a positioning slot on the side mold 90 for positioning the combined core mold 100; there are protruding boss structures on the left and right ends of the combined core mold 100, which are connected and positioned with the positioning slots of the side mold 90, and there are threaded holes on the boss structures, which can be connected to handles to facilitate the transportation of the combined core mold 100 during paving. After the combined core mold 100 is positioned, the foam is positioned. The two pieces of foam can be placed directly against the positioned combined core mold 100. The metal placeholders in the foam extend with positioning guides, which can be positioned in the positioning holes reserved on the side mold 90 to avoid the metal placeholders from slipping due to pressure during the curing process.

[0076] There are two side molds 90, namely, a left mold and a right mold, and both the left mold and the right mold are installed on the lower mold 80. Correspondingly, there are also two slide grooves 140, namely, a left slide groove and a right slide groove.

[0077] In some embodiments, a positioning hole is disposed on the upper mold 70 , and a positioning guide column 160 corresponding to the positioning hole is disposed on the lower mold 80 .

[0078] The upper mold 70 and the lower mold 80 can be molded together through the positioning holes and the positioning guide pins 160 .

[0079] Among them, the manufacturing process of the product is as follows: 1. Mold preparation: clean the molds and fiberglass boards required. 2. Preparation for paving: collect the raw materials and auxiliary materials needed for paving. 3. Paving: lay prepreg on the lower mold 80 and the combined core mold 100 respectively. 4. Combined core mold 100: position the combined core mold 100 with raw materials, and use the positioned combined core mold 100 to position and place the foam. 5. Combine the upper and lower molds: position the placeholder core mold 110 into the part, check the quality of product paving, and then combine the upper and lower molds and send them to the hot press. 6. Curing: adjust the hot press program to the set curing system to cure the product. 7. Demolding: open the upper mold after curing, and use tools to remove the combined core mold 100 and the placeholder core mold 110. 8. Processing: remove the resin flash on the product. From now on, the molded wingtip parts can be obtained. This molding process has low cost, stable technology, high pass rate, and can be mass-produced, which has advantages in both product research and development and market competition.

[0080] In summary, the forming mold of the wing tip of the variable thickness cavity foam sandwich structure provided in the embodiment of the present application includes an upper mold 70, a lower mold 80, a side mold 90, a combined core mold 100 and a placeholder core mold 110; the combined core mold 100 is placed between the upper mold 70 and the lower mold 80, wherein the combined core mold 100 includes a glass fiber board 1001 and a metal core mold 1002, and the glass fiber board 1001 and the metal core mold 1002 are connected by a pressure-sensitive tape; the side mold 90 is placed between the upper mold 70 and the lower mold 80, and is located on the side of the combined core mold 100, and is used to provide lateral pressure on the product to ensure the internal quality of the product side; the placeholder core mold 110 is placed between the upper mold 70 and the lower mold 80, and is located on both sides of the combined core mold 100, and is used to form cavities, lightening holes and connecting holes on the molding product, wherein the placeholder core mold 110 is a metal placeholder block. Compared with the prior art, the use of the molding mold of the embodiment of the present application to mold the variable thickness cavity foam sandwich structure wing tip not only has lower molding difficulty, simpler molding process, and lower cost, but also the obtained variable thickness cavity foam sandwich structure wing tip has better internal quality.

[0081] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0082] See also Figure 7The present application also provides an integrated molding method for a wing tip of a variable thickness hollow foam sandwich structure, which is used in a molding mold for a wing tip of a variable thickness hollow foam sandwich structure as described in any of the above embodiments, and the method comprises the following steps:

[0083] Step 101, laying a layer of demoulding tape on the upper mold, the lower mold, the side mold and the combined core mold respectively.

[0084] Among them, the upper mold, lower mold, metal core mold, side mold and glass fiber board surface of the mold need to be affixed with a layer of adhesive release cloth before laying, which is used to expel the air inside the product during the hot pressing process, ensure the internal and external quality of the product, and facilitate demolding.

[0085] Step 102, laying out the prepreg of the outer skin of the product on the lower mold, and performing pre-extraction after the laying is completed.

[0086] Step 103, laying circumferential layers with prepreg on two foams used to generate the foam sandwich area of ​​the product and the combined core mold, and pre-drawing is performed after the laying is completed, and metal placeholders are placed in the corresponding foams.

[0087] Among them, the product is laid on the lower mold and the combined core mold molding surface for raw material laying, foam placement and positioning (such as Figure 6 As shown, the carbon fiber prepreg layer 170 is laid on the molding surface of the lower mold and the combined core mold. Step 102 and step 103 can be performed simultaneously, that is, during laying, the combined core mold, two foams, and the lower mold can be laid at the same time, the prepreg of the product outer skin is laid on the lower mold, and the circumferential layer is laid on the combined core mold and the foam. After the layer is laid, pre-drawing is performed to tighten the prepreg to avoid excessive positioning due to excessive thickness of the prepreg during the subsequent positioning, and at the same time, the metal placeholder is placed in the corresponding foam.

[0088] Step 104, installing the side mold, the combined core mold and the two foams on the lower mold, and after installation, filling the R corner formed by the combined area of ​​the foam and the combined core mold with carbon fiber twisted filaments to supplement the mold surface.

[0089] Among them, due to the carbon fiber hoop layer will appear R angle at the corner, such as Figure 6 Therefore, it is necessary to fill the R angle formed by the combined area of ​​the foam and the combined core mold with carbon fiber twisted filaments 180 degrees to supplement the mold surface to ensure that the upper and lower mold surfaces of the product can be compacted during hot pressing.

[0090] In some embodiments, the step of installing the side mold, the combined core mold, and the two foams on the lower mold includes:

[0091] Installing the side mold to the corresponding position of the lower mold through the sliding groove on the lower mold;

[0092] The combined core mold is installed on the lower mold through the boss structure on the combined core mold and the positioning slots on the side mold;

[0093] The two foams are mounted on the lower mold through the positioning guide pins on the metal placeholder block and the positioning holes on the side mold.

[0094] Step 105, laying the skin prepreg of the upper part of the product on the combined core mold and the two foams, and installing the core mold stopper on the combined core mold.

[0095] Among them, after the combined core mold and foam are placed, the skin prepreg of the upper part of the product can be laid on the upper surface and prepared for mold closing, such as Figure 3 .

[0096] Step 106, installing the upper mold onto the lower mold for mold closing, and after the mold closing is completed, sending it to a hot press for cold pressing and curing, and demolding and processing after curing and molding to prepare a variable thickness cavity foam sandwich structure wing tip.

[0097] Among them, when closing the mold, you first need to place the core mold block in the left and right slots of the combined core mold. The function of the core mold block is to fix the combined core mold to prevent the core mold from warping and deformation during the curing process; the second function is to compact the combined core mold. When the length of the part is long, the two ends are compacted to ensure that the combined core mold presses the lower surface prepreg in place during the curing process. After the core mold block is placed, lift the upper mold, align the positioning guide column on the lower mold with the positioning hole of the upper mold to close the mold, and ensure the accuracy of the upper and lower mold positions. After the mold is closed, send it to the hot press for cold pressing, and observe the mold gap between the upper and lower molds. If the gap is too large, it means that there is interference with the carbon fiber clamping material at the front and rear edges of the wing tip (caused by loose paving). The upper mold needs to be opened, the excess carbon fiber prepreg is cut off, and the lower and upper molds are closed again to ensure that the upper and lower molds can be closed in place during hot pressing and the product is fully pressurized.

[0098] After the mold is closed, the curing program is started and curing begins. At this time, the pressure and temperature of the press are transmitted to the product through the upper and lower side molds. The resin begins to react under the pressure and temperature and gradually solidifies. Finally, the product is formed in one piece according to the size of each cavity of the mold.

[0099] In some embodiments, the curing and molding are followed by demoulding and processing to prepare a variable thickness cavity foam sandwich structure wing tip, including:

[0100] After curing and molding, the mold is lifted off the hot press by a forklift;

[0101] Open the upper mold, remove the side molds, and install the demoulding block;

[0102] The combined core mold and the metal placeholder block are taken out by a pin puller, and the product is processed to prepare a wing tip with a variable thickness cavity foam sandwich structure.

[0103] Specifically, after the curing is completed, the mold is lifted off the hot press by a forklift, the upper mold is opened, and demoulding begins. Figure 4 . Figure 4 For the big end of the product, remove the side mold at this end, install the demoulding block, and hold the product. Since there are threaded holes on the metal placeholder and the side end of the core mold, the metal placeholder and the combined core mold can be removed from the big end using a pin puller. Since the product is formed to a net size, it is sent for processing, and the overflowed resin flash is removed to obtain the final product. During the manufacturing process, it is necessary to pay attention to controlling the foam profile. The contour of the foam profile should be controlled between ±0.2mm. A larger or smaller profile will cause local underpressure of the product.

[0104] In some embodiments, removing the combined core mold and the metal placeholder block by a pin puller includes:

[0105] The metal place-taking block and the metal core mold in the combined core mold are taken out by the pin puller, and then the glass fiber board in the combined core mold is taken out.

[0106] In some embodiments, before laying the hoop layer with prepreg on the two foams and the combined core mold, the method further includes:

[0107] A layer of adhesive film is laid on the two foams respectively.

[0108] Among them, a layer of adhesive film needs to be laid on the surface of the foam before paving to prevent the foam from absorbing too much glue and causing pinholes on the product surface.

[0109] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0110] In specific implementation, the present application is not limited by the execution order of the various steps described. If no conflict occurs, some steps can be performed in other orders or simultaneously.

[0111] As can be seen from the above, the one-piece molding method of the variable thickness hollow foam sandwich structure wing tip provided in the embodiment of the present application is, first, a layer of demoulding tape is laid on the upper mold, the lower mold, the side mold and the combined core mold respectively, and then the prepreg of the outer skin of the product is laid on the lower mold, and pre-extraction is performed after the laying is completed, and then the circumferential layer is laid with prepreg on the two foams and the combined core mold used to generate the foam sandwich area of ​​the product, and pre-extraction is performed after the laying is completed, and the metal placeholder block is placed in the corresponding foam, and then the side mold, the combined core mold and the two foams are installed on the lower mold. After installation, carbon fiber twisted wire strips are filled at the R corner formed by the combined area of ​​the foam and the combined core mold to supplement the mold surface, and then the skin prepreg of the upper part of the product is laid on the combined core mold and the two foams, and the core mold stopper is installed on the combined core mold, and finally the upper mold is installed on the lower mold for mold closing, and after the mold closing is completed, it is sent to the hot press for cold pressing and curing, and demolding and processing are performed after curing and molding to prepare the variable thickness hollow foam sandwich structure wing tip. Compared with the prior art, the molding method of the embodiment of the present application is used to mold the variable thickness cavity foam sandwich structure wing tip, which not only has lower molding difficulty, simpler molding process, and lower cost, but also the obtained variable thickness cavity foam sandwich structure wing tip has better internal quality.

[0112] The above is a detailed introduction to the molding mold and one-piece molding method of the wing tip of a variable thickness hollow foam sandwich structure provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A forming die for a wing tip of a variable thickness cavity foam sandwich structure, characterized in that: It includes an upper mold, a lower mold, a side mold, a combined core mold and a placeholder core mold; The combined core mold is placed between the upper mold and the lower mold, wherein the combined core mold includes a glass fiber board and a metal core mold, and the glass fiber board and the metal core mold are connected by a pressure-sensitive tape; The side mold is placed between the upper mold and the lower mold and is located on the side of the combined core mold, and is used to provide lateral pressure on the product to ensure the internal quality of the product side; The placeholder core mold is placed between the upper mold and the lower mold and located on both sides of the combined core mold, and is used to form cavities, lightening holes and connecting holes on the molded product, wherein the placeholder core mold is a metal placeholder block.

2. The forming mold for the wing tip of the variable thickness cavity foam sandwich structure according to claim 1, characterized in that: Also included is a core mold stopper; The core mold stopper is placed between the upper mold and the lower mold and is located on the side of the combined core mold, and is used to fix and compact the combined core mold.

3. The forming mold for the wing tip of the variable thickness cavity foam sandwich structure according to claim 1, characterized in that: It also includes a demoulding tool, which is used to demould the combined core mold and the placeholder core mold after the product is formed, ensuring smooth demoulding without damaging the product.

4. The forming mold for the wing tip of the variable thickness cavity foam sandwich structure according to claim 1, characterized in that: The areas on the upper mold, the lower mold, the side mold and the combined core mold for laying the adhesive release cloth are reserved with a thickness of one layer of release cloth.

5. The forming mold for the wing tip of the variable thickness cavity foam sandwich structure according to claim 1, characterized in that: The lower mold is provided with a slide groove, and the slide groove is used to facilitate the installation of the side mold on the lower mold; The combined core mold is provided with a boss structure, and the side mold is provided with a positioning slot, wherein the boss structure is provided with a threaded hole; The metal placeholder block is provided with a positioning guide column, and the side mold is provided with a positioning hole.

6. A method for integrally molding a wing tip of a variable thickness hollow foam sandwich structure, used in the integrally molding mold of the wing tip of a variable thickness hollow foam sandwich structure according to any one of claims 1 to 5, characterized in that: The method comprises: Lay a layer of demoulding tape on the upper mold, lower mold, side mold and combined core mold respectively; Laying the prepreg of the outer skin of the product on the lower mold, and performing pre-extraction after the laying is completed; Laying circumferential layers with prepreg on two foams and the combined core mold for forming the foam core area of ​​the product, and pre-drawing after the laying, while placing metal placeholders in the corresponding foams; The side mold, the combined core mold and the two foams are installed on the lower mold, and after installation, carbon fiber twisted filaments are filled in the R corner formed by the combined area of ​​the foam and the combined core mold to supplement the mold surface; Laying the skin prepreg of the upper part of the product on the combined core mold and the two foams, and installing the core mold stopper on the combined core mold; The upper mold is mounted on the lower mold for mold closing, and after the mold closing is completed, it is sent to a hot press for cold pressing and curing. After curing and molding, it is demoulded and processed to prepare a variable thickness cavity foam sandwich structure wing tip.

7. The one-piece molding method of the variable thickness cavity foam sandwich structure wing tip according to claim 6, characterized in that: The step of installing the side mold, the combined core mold and the two foams on the lower mold comprises: Install the side mold to the corresponding position of the lower mold through the sliding groove on the lower mold; The combined core mold is installed on the lower mold through the boss structure on the combined core mold and the positioning slots on the side mold; The two foams are mounted on the lower mold through the positioning guide pins on the metal placeholder block and the positioning holes on the side mold.

8. The one-piece molding method of the variable thickness cavity foam sandwich structure wing tip according to claim 6, characterized in that: After the curing and molding, demoulding and processing are performed to prepare a variable thickness cavity foam sandwich structure wing tip, including: After curing and molding, the mold is lifted off the hot press by a forklift; Open the upper mold, remove the side molds, and install the demoulding block; The combined core mold and the metal placeholder block are taken out by a pin puller, and the product is processed to prepare a wing tip with a variable thickness cavity foam sandwich structure.

9. The one-piece molding method of the variable thickness cavity foam sandwich structure wing tip according to claim 8, characterized in that: The method of removing the combined core mold and the metal placeholder block by using a pin puller comprises: The metal place-taking block and the metal core mold in the combined core mold are taken out by the pin puller, and then the glass fiber board in the combined core mold is taken out.

10. The one-piece molding method of the variable thickness cavity foam sandwich structure wing tip according to claim 6, characterized in that: Before laying the hoop layer with prepreg on the two foams and the combined core mold, the method further comprises: A layer of adhesive film is laid on the two foams respectively.

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