Winding one-way plate forming method and forming tool

Abstract

The invention provides a winding one-way plate forming method and a forming tool. The winding one-way plate forming method comprises the steps that fiber winding and pressurization are conducted on the forming tool to form two layers of blank plates; pre-curing the blank plates, cutting off fibers for connecting the two layers of blank plates, and finally curing the blank plates; cutting and processing the blank plate into a one-way plate according to a preset size; cutting and processing the reinforcing sheet; the reinforcing sheet is bonded to the one-way plate and cured; and cutting and processing the one-way plate into a one-way plate standard test sample. According to the method, a segmented forming method is adopted, the blank plates are pre-cured, after pre-curing, the fibers for connecting the two layers of blank plates are cut off, and finally the blank plates are finally cured, so that the problem of tilting deformation caused by the fact that fiber stress is not released in time is solved.

Description

Technical Field

[0001] The invention relates to the technical field of fiber-wound unidirectional plates, and in particular to a forming method and a forming tool for a wound unidirectional plate. Background Art

[0002] Filament-wound solid engine casings are increasingly used in missile weapons or rocket engines. Along with this, the performance verification and testing of its raw materials are becoming more and more urgent. Among them, the fiber multifilament sample can directly reflect the good or bad performance of the fiber monofilament, and the performance of the fiber-wound unidirectional board can directly reflect the strength of the matching between the fiber and the resin. The performance of carbon fiber unidirectional board is the "gold standard" for the evaluation of fiber performance of winding products and an important indicator for product design and evaluation of product performance. It is extremely important to accurately produce and test the unidirectional board and truly reflect the fiber performance and resin matching. Usually, the performance test of carbon fiber unidirectional board includes 0° tensile strength, 0° tensile modulus, 90° tensile strength, 90° tensile modulus, 0° compression strength, 0° compression modulus, 90° compression strength, 90° compression modulus, 0° bending strength, 0° bending modulus and interlaminar shear strength. If the performance test results of the fiber-wound unidirectional board are abnormal due to the sample production, it will directly affect the use of the raw materials, and ultimately affect the product performance and usage.

[0003] Existing fiber-wound unidirectional boards all adopt a method of one-time curing and segmented bonding of reinforcement sheets to form unidirectional board test specimens. There are problems such as the unidirectional board is easy to warp and deform, the reinforcement sheet has low bonding strength and is skewed, resulting in easy pulling off during testing. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide a winding unidirectional plate forming method and forming tooling. The method adopts a segmented forming method, first pre-curing the embryonic plate, and after pre-curing, the fibers connecting the two layers of the embryonic plate are cut off, and finally the embryonic plate is finally cured, thereby reducing the warping and deformation problem caused by the failure to release the fiber stress in time.

[0005] In order to solve the above technical problems, in a first aspect, the present invention provides a winding unidirectional plate forming method, comprising:

[0006] The fiber is wound and pressed on a forming tool to form a two-layer embryonic board;

[0007] Pre-solidify the embryonic plate, cut off the fibers connecting the two layers of the embryonic plate, and finally solidify the embryonic plate;

[0008] Cut and process the embryonic board into one-way board according to the preset size;

[0009] Cutting and processing of reinforcement sheets;

[0010] Bonding the reinforcing sheet to the one-way slab and curing it;

[0011] The one-way slabs are cut and processed into standard test specimens of one-way slabs.

[0012] In some embodiments, the method of performing fiber winding on a forming tool includes: the distance between the starting point and the end point of the fiber winding and the two side boundaries of the winding area of ​​the forming tool is a.

[0013] In some embodiments, the method for pre-curing the embryonic plate includes: placing the molding tool and the embryonic plate fixed on the molding tool into a curing furnace, starting the heating system, adjusting the heating rate to 1-2°C / min, first heating the temperature to 80-90°C, keeping it warm for 1-3 hours, then heating the temperature to 100-120°C, keeping it warm for 3-5 hours, stopping heating, cooling to below 50°C, and taking out the molding tool.

[0014] Furthermore, the method for cutting off the fibers connecting the two layers of embryonic plates includes: using a pneumatic grinder to cut off all the fibers exposed on the outside along the side of the tooling.

[0015] Furthermore, the method for final curing the embryonic board includes: placing the cut unidirectional board and tooling into the curing furnace again, starting the heating system, adjusting the heating rate to 1-2°C / min, selecting the corresponding curing system according to the resin type, and after completing the heating and insulation, cooling it to below 50°C with the furnace and taking it out.

[0016] In some embodiments, the method of bonding the reinforcing sheet to the one-way board and curing the same includes:

[0017] The bonding area of ​​the reinforcement sheet and the corresponding bonding area of ​​the one-way plate are roughened by sandblasting;

[0018] Clean the one-way board and reinforcement sheet and let them dry;

[0019] Cutting film;

[0020] Paste the adhesive film;

[0021] Bond the reinforcement sheet to the one-way slab.

[0022] Furthermore, the method of bonding the reinforcing sheet to the one-way board and curing the same includes:

[0023] The one-way board with the reinforcement sheet bonded is packed into a vacuum bag and vacuumized;

[0024] The vacuum-proof one-way board is transferred into the curing furnace for curing.

[0025] In the second aspect, the present invention provides a winding unidirectional plate forming tooling, comprising a winding plate and two pressing plates, wherein grooves and fixing holes are provided on the upper and lower surfaces of the winding plate, and the fixing holes are arranged on both sides outside the grooves, and the grooves are used for winding fibers, and the fixing holes are used for fixing the pressing plate on the winding plate, and a boss is provided on the pressing plate, and the boss is arranged corresponding to the groove, and the boss is used for extruding the fibers wound on the winding plate.

[0026] Furthermore, a reverse top hole is provided on the pressing plate, and the reverse top hole is used to separate the pressing plate from the winding plate.

[0027] Furthermore, a gasket is arranged between the winding plate and the pressing plate, and the gasket is arranged at the fixing hole.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention adopts a segmented forming method, first pre-curing the embryonic plate, and after pre-curing, the fibers connecting the two layers of embryonic plates are cut off. After cutting, the embryonic plate clamped on the forming tooling will release a certain stress and shrink, and finally the embryonic plate is finally cured, thereby reducing the warping and deformation problem caused by the failure to release the fiber stress in time.

[0030] 2. When the present invention winds the fiber, a certain distance is reserved between the starting point and the end point of the fiber winding and the two sides of the winding area of ​​the forming tooling to prevent the resin on the fiber from gathering at the edge when the tooling squeezes the fiber, resulting in a higher fiber resin content at the edge, which does not meet the production requirements of the unidirectional board.

[0031] 3. The present invention manufactures a larger-sized one-way board, directly bonds a reinforcing plate to the large-sized one-way board, and then cuts the one-way board with the reinforcing plate bonded thereto into a one-way board standard test specimen. Compared with first cutting and then bonding the reinforcing plate, the one-way board standard test specimen of the present invention is more square, and the reinforcing plate is precisely bonded to both ends of the one-way board standard test specimen, thereby avoiding the problem of inaccurate subsequent test results caused by the skewed bonding of the reinforcing plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the front view of the present invention.

[0033] Figure 2 A top view of the present invention;

[0034] Figure 3 It is a front view of the wrapping plate of the present invention;

[0035] Figure 4 A top view of a winding plate of the present invention;

[0036] Figure 5 It is a front view of the pressing plate of the present invention;

[0037] Figure 6 It is a top view of the pressing plate of the present invention.

[0038] Figure numerals: winding plate 1; pressing plate 2; handle 3; gasket 4; bolt 5; top hole 6; groove 7; boss 8; fixing hole 9. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] like Figure 1 As shown, the present invention provides a winding unidirectional plate forming tool, including a winding plate 1 and two pressing plates 2, as shown in Figure 2 , 3 As shown, the upper and lower surfaces of the winding plate 1 are provided with grooves 7 and fixing holes 9. The groove 7 is provided in the middle of the winding plate 1, and the fixing holes 9 are arranged on both sides outside the groove 7, close to the edge of the winding plate 1. The groove 7 is used for winding fibers, and the fixing holes 9 are used for fixing the pressing plate 2 on the winding plate 1. Figure 5 , 6 As shown, a boss 8 is provided on the pressing plate 2 , and the boss 8 is arranged corresponding to the groove 7 . The boss 8 is used to squeeze the fiber wound on the winding plate 1 .

[0041] like Figure 6 As shown, a reverse top hole 6 is provided on the pressing plate 2 , and the reverse top hole 6 is used to separate the pressing plate 2 from the wrapping plate 1 , that is, the pressing plate 2 can be lifted up by screwing a bolt 5 into the reverse top hole 6 .

[0042] like Figure 1 As shown, a gasket 4 is arranged between the winding plate 1 and the pressing plate 2. The gasket 4 is arranged at the fixing hole 9, that is, close to the edges on both sides of the winding plate 1. The gasket 4 can accurately control the thickness of the embryo plate while ensuring that the pressing plate 2 applies pressure to the fiber.

[0043] The present invention provides a winding unidirectional plate forming method, comprising:

[0044] S1. Winding the fibers on the forming tool and applying pressure to form a two-layer embryonic plate; specifically including:

[0045] S11, assembly of molding tooling: clean the surfaces of the wrapping plate 1 and the pressing plate 2, then paste polytetrafluoroethylene demoulding cloth on the groove 7 (i.e., the one-way plate wrapping area) of the wrapping plate 1 and the boss 8 of the pressing plate 2, connect the wrapping plate 1 and the handle 3 into a whole through bolts 5 and nuts, clamp the handle 3 on the wrapping machine chuck, and tighten the CNC wrapping machine chuck;

[0046] S12, according to the demand, select the corresponding fiber and resin for fiber unidirectional board winding: select the corresponding fiber and resin, pass the fiber through the CNC winding machine yarn path, prepare the resin according to the corresponding resin preparation ratio, pour the prepared resin into the fiber impregnation glue tank, set the appropriate tension, turn on the CNC winding machine tension control system, call the winding program, and wind the fiber unidirectional board. The number of winding layers needs to be determined and adjusted according to the type of fiber yarn, the number of fiber yarn strands, the fiber yarn width and the thickness of the winding layer. The starting point of the winding is about 10 mm from the side wall on one side of the groove 7, and the end point is about 10 mm from the side wall on the other side of the groove 7. The winding length is about 280 mm. Cut the head yarn after winding.

[0047] It is understandable that after the fiber winding is completed, during the process of the pressing plate 2 squeezing the fiber, the resin on the fiber will be squeezed to the two sides of the groove 7. If the fiber extends to the two sides of the groove 7, the resin content in the fiber close to the two sides of the groove 7 is relatively high, which does not meet the molding requirements of the one-way board. Therefore, the present invention reserves a certain distance between the starting point and the end point of the winding and the two sides of the groove 7, so that the resin content in the entire embryonic board meets the requirements.

[0048] S13. Apply pressure using the pressure plate 2: Use 10 M12 screws to assemble the pressure plate 2 and the wrapping plate 1 into place. Before assembling the pressure plate 2, use 1 (10 in total) 1mm thick gasket 4 (adjusted according to the thickness of the one-way plate) between the bolts 5 between the pressure plate 2 and the wrapping plate 1 for limiting. Then tighten the two pressure plates 2 with the bolts 5 (torque is required to ensure that the torque of the 10 bolts 5 is the same, the torque value is 40 to 90 N·m, and the bolts 5 are tightened symmetrically, and the torque increases step by step by 10 N·m) to ensure that the thickness of the embryo plate is uniform.

[0049] S2, pre-curing the embryonic plate, cutting off the fibers connecting the two layers of the embryonic plate, and finally curing the embryonic plate; specifically including:

[0050] S21. Pre-curing the embryonic plate: Place the molding tool and the embryonic plate fixed on the molding tool into the curing furnace, start the heating system, adjust the heating rate to 1-2°C / min, first heat the temperature to 80-90°C, keep it warm for 1-3h, then heat the temperature to 100-120°C, keep it warm for 3-5h, stop heating, cool to below 50°C, and take out the molding tool.

[0051] S22. Cut off the fibers connecting the two layers of the embryonic plates: Use a pneumatic grinder to cut off all the fibers exposed on the outside along the side of the tooling.

[0052] S23, final curing of the embryonic board: put the cut one-way board and the tooling into the curing furnace again, start the heating system, adjust the heating rate to 1-2℃ / min, select the corresponding curing system according to the resin type, and after completing the heating and heat preservation, cool it to below 50℃ with the furnace and take it out.

[0053] It can be understood that by adopting the segmented molding method, the embryonic plate is first pre-cured. After pre-curing, the fibers connecting the two layers of embryonic plates are cut off. After cutting, the embryonic plate clamped on the molding tool will release a certain stress and shrink. Finally, the embryonic plate is finally cured, thereby reducing the warping and deformation problem caused by the failure to release the fiber stress in time.

[0054] S3. Cutting and processing the embryonic board into one-way boards according to the preset size; specifically including:

[0055] After the solidification is completed and the qualified blank is processed according to the following dimensions:

[0056] (1) 0° tensile unidirectional plate machine: (230±0.3)mm (fiber direction)×(250±0.5)mm×1mm (thickness, not processed);

[0057] (2) 90° tensile test specimen machine size: (170±0.3) mm×(25±0.3) mm (fiber direction)×2 mm;

[0058] (3) 0° compression unidirectional plate machine plus: (140±0.3) mm (fiber direction) × (250±0.5) mm × 2 mm (thickness, not processed);

[0059] (4) 90° compression unidirectional plate machine plus: (140±0.3)mm (perpendicular to the fiber direction)×(250±0.5)mm×2mm (thickness, not processed);

[0060] (5) 0° bending test specimen machining: (80±0.3) mm (fiber direction) × 12.5 (±0.2) mm × 2 mm;

[0061] (6) Interlaminar shear test specimen: (30 ± 1) mm (fiber direction) × 10 (± 0.2) mm × 2 mm.

[0062] S4. Cutting and processing the reinforcement sheet; specifically including:

[0063] The reinforcing sheets of the composite material with a size of 1020×2040×2 mm were processed into reinforcing sheets with a size of 50×250×2 mm (tensile specimen reinforcing sheet) and 63×250×2 mm (compression specimen reinforcing sheet) for standby use.

[0064] S5. Bonding the reinforcing sheet to the one-way board and curing it; specifically including:

[0065] S51. Sandblast the bonding area of ​​the reinforcement sheet and the corresponding bonding area of ​​the one-way plate to make them rough without damaging the fibers;

[0066] S52. Clean the one-way board and the reinforcing sheet and dry them: Use lint-free paper dipped in anhydrous ethanol or ethyl acetate to wipe the entire surface of the one-way board and the reinforcing sheet clean, and leave them at room temperature for 10 to 20 minutes;

[0067] S53, cutting adhesive film: Cut the adhesive film of corresponding size according to the size of the reinforcement sheet of each sample for use. Each 0° or 90° tensile unidirectional board corresponds to 4 pieces of adhesive film (250mm×50mm), and each 0° compression unidirectional board and 90° compression unidirectional board corresponds to 4 pieces of adhesive film (250×63mm);

[0068] S54, sticking the film: tear off the silicone oil paper on one side of the film, stick the film of the corresponding size to the surface of the reinforcing sheet of the corresponding size, then press the film to make the film and the reinforcing sheet initially stick together, tear off the silicone oil paper on the side of the film that is exposed outside, and the film layer exposed outside should face up;

[0069] S55. Bond the reinforcing sheet to the one-way plate: bond the 0° tensile specimen reinforcing sheet and the 0° / 90° compression specimen reinforcing sheet to the 0° tensile one-way plate and the 0° / 90° compression one-way plate respectively, and press the two to make them close after bonding.

[0070] S56, packing the one-way board with the reinforcement sheet bonded thereto into a vacuum bag and performing vacuum treatment;

[0071] S57. Transfer the vacuum-evacuated qualified one-way boards into the curing furnace for curing. After curing, take the one-way boards out of the curing furnace, clean the vacuum bags, breathable felt, and adhesive tape, and gently tear off the positioning strips, pressure-sensitive adhesive, release cloth, and sealing black glue, and clean the surface of the one-way boards. Do not damage the fibers during the cleaning process.

[0072] S6. Cut and process the one-way slab into one-way slab standard test specimens.

[0073] The one-way plate with the reinforcement sheet bonded and the one-way plate that can be directly machined are machined for the one-way plate standard test sample. The standard sample size is as follows (the size standards are respectively implemented: tension: GB / T3354; compression: GB / T3856; bending: GB / T3356; interlaminar shear strength: JC / T773):

[0074] 0° tensile specimens ((230±0.3)mm (fiber direction)×(12.5±0.3)mm×1mm), 10 pieces;

[0075] 90° tensile specimens ((170±0.3)mm×(25±0.3)mm(fiber direction)×2mm), 10 pieces;

[0076] 0° compression specimens ((140±0.3)mm (fiber direction)×(6±0.3)mm×2mm)), 10 pieces;

[0077] 90° compression specimens (140±0.3)mm (perpendicular to fiber direction)×(6±0.3)mm×2mm), 7 pieces;

[0078] 0° bending specimens ((80±0.3)mm (fiber direction)×12.5(±0.2)mm×2mm)), 7 pieces;

[0079] 0° interlaminar shear specimens ((30±1)mm (fiber direction)×10(±0.2)mm×2mm), 7 pieces.

[0080] It can be understood that the present invention manufactures a larger-sized one-way board, directly bonds a reinforcing plate to the large-sized one-way board, and then cuts the one-way board with the reinforcing plate bonded into a one-way board standard test specimen. Compared with first cutting and then bonding the reinforcing plate, the one-way board standard test specimen of the present invention is more square, and the reinforcing plate is precisely bonded to both ends of the one-way board standard test specimen, avoiding the problem of inaccurate subsequent test results caused by the skewed bonding of the reinforcing plate.

[0081] The above processed one-way board standard test specimens are subjected to performance tests according to the following standards:

[0082] Test 0° / 90° tensile strength and modulus, and implement standard GB / T 3354-2014;

[0083] Test 0° / 90° compression strength and modulus, and implement standard BG / T 3856-2005;

[0084] Test 0° bending strength according to GB / T 3356-2014;

[0085] Test 0° bending modulus according to GB / T 3356-2005;

[0086] The interlaminar shear strength test is carried out in accordance with the standard JC / T 773-2010.

[0087] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for forming a winding unidirectional plate, characterized in that: include: The fiber is wound and pressed on a forming tool to form a two-layer embryonic board; Pre-solidify the embryonic plate, cut off the fibers connecting the two layers of the embryonic plate, and finally solidify the embryonic plate; Cut and process the embryonic board into one-way board according to the preset size; Cutting and processing of reinforcement sheets; Bonding the reinforcing sheet to the one-way slab and curing it; The one-way slabs are cut and processed into standard test specimens of one-way slabs.

2. The method for forming a wound unidirectional plate according to claim 1, characterized in that: The method for performing fiber winding on a forming tool comprises: the distance between a starting point and an end point of the fiber winding and two side boundaries of a winding area of ​​the forming tool is a.

3. The method for forming a wound unidirectional plate according to claim 1 or 2, characterized in that: The method for pre-curing the embryo plate includes: placing the molding tool and the embryo plate fixed on the molding tool into the curing furnace, starting the heating system, adjusting the heating rate to 1-2°C / min, first heating the temperature to 80-90°C, keeping it warm for 1-3 hours, then heating the temperature to 100-120°C, keeping it warm for 3-5 hours, stopping heating, cooling to below 50°C, and taking out the molding tool.

4. The method for forming a wound unidirectional plate according to claim 3, characterized in that: The method of cutting off the fibers connecting the two layers of the embryonic board includes: using a pneumatic grinder to cut off all the fibers exposed on the outside along the side of the tooling.

5. The method for forming a wound unidirectional plate according to claim 4, characterized in that: The method for final curing the embryonic board includes: placing the cut unidirectional board and the tooling into the curing furnace again, starting the heating system, adjusting the heating rate to 1-2°C / min, selecting the corresponding curing system according to the resin type, and after completing the heating and heat preservation, cooling with the furnace to below 50°C and taking it out.

6. The method for forming a wound unidirectional plate according to claim 1 or 2, characterized in that: Methods for bonding and curing the reinforcing sheet to the one-way board include: The bonding area of ​​the reinforcement sheet and the corresponding bonding area of ​​the one-way plate are roughened by sandblasting; Clean the one-way board and reinforcement sheet and let them dry; Cutting film; Paste the adhesive film; Bond the reinforcement sheet to the one-way slab.

7. The method for forming a wound unidirectional plate according to claim 6, characterized in that: Methods for bonding and curing the reinforcing sheet to the one-way board include: The one-way board with the reinforcement sheet bonded is packed into a vacuum bag and vacuumized; The vacuum-proof one-way board is transferred into the curing furnace for curing.

8. A wrapping unidirectional plate forming tool for the wrapping unidirectional plate forming method according to any one of claims 1 to 7, characterized in that: The invention comprises a winding plate (1) and two pressing plates (2), wherein the upper and lower surfaces of the winding plate (1) are provided with grooves (7) and fixing holes (9), wherein the fixing holes (9) are arranged on both sides outside the grooves (7), wherein the grooves (7) are used for winding fibers, and the fixing holes (9) are used for fixing the pressing plates (2) on the winding plate (1), wherein a boss (8) is arranged corresponding to the grooves (7), and wherein the boss (8) is used for extruding the fibers wound on the winding plate (1).

9. The wrapping unidirectional plate forming tool according to claim 8, characterized in that: The pressing plate (2) is provided with a reverse top hole (6), and the reverse top hole (6) is used to separate the pressing plate (2) from the wrapping plate (1).

10. The wrapping unidirectional plate forming tool according to claim 8, characterized in that: A gasket (4) is arranged between the winding plate (1) and the pressing plate (2), and the gasket (4) is arranged at the fixing hole (9).

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