Honeycomb sandwich composite material thin-layer antenna cover and forming method thereof

Abstract

The present invention relates to the field of antenna cover technology, in particular to a thin layer antenna cover made of honeycomb sandwich composite material and a forming method thereof, comprising an outer skin, and further comprising: the outer skin is arranged in a cover shape; a plurality of honeycomb cores are glued and arranged inside the cover shape of the outer skin; an inner skin is glued and arranged inside the honeycomb core; a plurality of metal embedded parts are arranged in a circular array and glued and fixed on the outer side wall of the outer skin, and positioning holes are penetrated on the metal embedded parts; the outer skin is glued with the honeycomb core, the inner skin, and the metal embedded parts by using modified epoxy resin film (or modified cyanate film). This device enables the antenna cover to be used normally in the S band (2-4GHz), mechanical and temperature environments, thereby helping to improve the use environment range of the antenna cover.

Description

Technical Field

[0001] The invention relates to the field of antenna covers, and in particular to a thin-layer antenna cover made of a honeycomb sandwich composite material and a molding method thereof. Background Art

[0002] The radar antenna cover is a key component to ensure the normal operation of the radar antenna system. The antenna cover needs to have dielectric properties, thermal shock resistance, mechanical properties, rain erosion resistance, manufacturing feasibility, etc., and factors such as weight and price must also be considered. In order to improve the anti-interference ability of electronic equipment, the antenna cover is required to have broadband wave transmission characteristics.

[0003] The existing antenna cover arm structure is mainly composed of a thin-wall structure, a sandwich structure and a multi-layer structure. In order to solve the normal use of the antenna cover in the S band (2-4GHz), mechanical and temperature environment, and because the cover body is a semi-closed rotating body structure, in order to ensure the product molding accuracy and demolding, the present invention provides a honeycomb sandwich composite material thin layer antenna cover and a molding method thereof. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a thin-layer antenna cover made of honeycomb sandwich composite material and a molding method thereof.

[0005] In a first aspect, the present invention provides a thin-layer radome of a honeycomb sandwich composite material, comprising an outer skin, and further comprising:

[0006] The outer skin is arranged in a hood shape;

[0007] A plurality of honeycomb cores are glued and arranged inside the hood-shaped outer skin;

[0008] An inner skin, glued and arranged inside the honeycomb core;

[0009] A plurality of metal embedded parts are arranged in a circumferential array and are glued and fixed to the outer side wall of the outer skin, and positioning holes are penetrated through the metal embedded parts;

[0010] The outer skin is bonded to the honeycomb core, the inner skin and the metal embedded parts by using modified epoxy resin film (or modified cyanate film).

[0011] Preferably, it also includes:

[0012] The outer skin and the inner skin both use low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg as skin material.

[0013] Preferably, it also includes:

[0014] The honeycomb core adopts aramid paper honeycomb core as core material.

[0015] In a second aspect, a method for forming a thin-layer antenna cover of a honeycomb sandwich composite material is provided, the forming method comprising the following steps:

[0016] Step 1, mold assembly and mold processing: after wiping the release agent on the surface of the split mold, the split mold is spliced ​​and fixed, and then the mold gap is checked with a feeler gauge to confirm that the mold surface and the engraved lines are intact;

[0017] Step 2: Cutting and laying out the outer skin: Lay out the cut outer skin sheets according to the design requirements of the laying angle to form the outer skin, and then seal the bag for vacuum testing. The vacuum degree is required to drop no more than -0.04 bar within 5 minutes after being pumped to -0.950 bar.

[0018] Step 3: Curing the outer skin: Put the assembled and sealed outer skin into a curing furnace, and after connecting the vacuum, cure it according to the set curing parameters;

[0019] Step 4: Honeycomb interlayer and metal inlay bonding: After cleaning the outer skin, the metal embedded parts and the honeycomb core and the inner skin are connected by stacking with a modified epoxy resin film (or a modified cyanate film), and then placed into the split mold, and the vacuum degree is tested after the bag is sealed;

[0020] Step 5, inner skin curing: put the sealed inner skin into a curing furnace, and after connecting the vacuum, cure it according to the set curing parameters;

[0021] Step 6: demoulding parts: after curing is completed, the split mold is disassembled and demoulded;

[0022] Step 7: Post-processing and painting: Use a CNC milling machine to inspect the product after processing, and then give the product a final paint job.

[0023] Preferably, the split mold comprises:

[0024] A bottom mold, on which a plurality of side sliding blocks are arranged in a circumferential array;

[0025] A plurality of positioning side sliders are arranged in a circular array and are respectively arranged between adjacent side sliders at intervals, and positioning grooves are symmetrically opened on the inner walls of the positioning side sliders;

[0026] The upper cover plate is fixed to the tops of all the positioning side sliders and all the side sliders by means of positioning pins and bolts, so as to connect and fix the bottom mold and the positioning side sliders, the side sliders and the upper cover plate.

[0027] Preferably, the step 4 specifically includes:

[0028] A1. After the honeycomb core is shaped and dried, it is symmetrically prepared;

[0029] A2. Clean the surface of the outer skin to be bonded with acetone, and lay a modified epoxy resin film (or modified cyanate ester film) on the bonding surface;

[0030] A3, laying the honeycomb core onto the modified epoxy resin film (or modified cyanate ester film) at a designated position, aligning and pre-extracting;

[0031] A4, wrapping the outer contour of the metal embedded part that has been surface treated with a modified epoxy resin film (or a modified cyanate ester film) and a glass fiber fabric prepreg and placing it in the positioning groove;

[0032] A5, laying the modified epoxy resin film (or modified cyanate ester film) on the surface of the honeycomb core and the metal embedded parts, and then laying the inner skin;

[0033] A6. Install the upper cover plate, and position the metal embedded parts, the upper cover plate, and the positioning side slider by passing the positioning pins through the positioning holes. Finally, seal the bag and perform vacuum testing.

[0034] Preferably, the curing parameters are set according to the types of resins specifically selected for the outer skin and the inner skin.

[0035] Preferably, the step A3 further comprises:

[0036] Pay attention to the connection of the honeycomb core at the honeycomb joints to avoid step differences caused by extrusion, so as to ensure the uniformity of the thickness of the honeycomb core.

[0037] Preferably, the ply angle design requirements in step 2 specifically include:

[0038] The total number of layers of the outer skin stacking is n layers of outer skin sheets, and the outer skin sheets are low-dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepregs, which are connected by butt joint, and then mold release cloth-non-porous isolation membrane-air permeable felt are placed in sequence;

[0039] The low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg has a joint requirement of less than or equal to 1 mm.

[0040] Preferably, the step 4 further comprises:

[0041] The inner skin is a low-dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg material with a total stacking number of n layers.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The antenna cover of the present invention uses low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg combined with aramid paper (Nomex) honeycomb core as the core material. Due to its high strength-to-weight ratio, good corrosion resistance and other favorable properties, the antenna cover can be used normally in the S band (2-4GHz), mechanical and temperature environments, which is beneficial to improve the use environment range of the antenna cover.

[0044] 2. The present invention designs a split mold to ensure smooth demoulding of the product, which not only improves production efficiency but also solves the demoulding problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic structural diagram of the antenna cover of the present invention.

[0046] Figure 2 It is a schematic diagram of the structure of the cross-section of the antenna cover of the present invention.

[0047] Figure 3 For the present invention Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0048] Figure 4 It is a structural schematic diagram of the split mold of the present invention.

[0049] Figure 5 It is a schematic diagram of the molding method of the present invention.

[0050] In the figure: 1. outer skin; 2. honeycomb core; 3. inner skin; 4. metal embedded parts; 5. bottom mold; 6. positioning side slider; 601, positioning groove; 7. side slider; 8. upper cover plate. DETAILED DESCRIPTION

[0051] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0052] like Figures 1 to 3 The thin-layer radome of the honeycomb sandwich composite material shown comprises an outer skin 1 and also comprises:

[0053] The outer skin 1 is arranged in a hood shape;

[0054] A plurality of honeycomb cores 2 are glued and arranged inside the hood-shaped outer skin 1;

[0055] An inner skin 3 is glued and arranged inside the honeycomb core 2;

[0056] A plurality of metal embedded parts 4 are arranged in a circumferential array and are glued and fixed to the outer wall of the outer skin 1. Positioning holes are provided through the metal embedded parts 4.

[0057] The outer skin 1 and the honeycomb core 2, the inner skin 3 and the metal embedded parts 4 are all bonded by using modified epoxy resin film (or modified cyanate film).

[0058] As an optional embodiment, it also includes:

[0059] The outer skin 1 and the inner skin 3 both use low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg as the skin material.

[0060] As an optional embodiment, it also includes:

[0061] The honeycomb core 2 uses aramid paper honeycomb core as core material.

[0062] The existing radome arm structure mainly consists of a thin-wall structure, a sandwich structure and a multi-layer structure. In order to solve the problem of normal use of the radome in the S-band (2-4GHz), mechanical and temperature environment, and because the cover body is a semi-closed rotating body structure, in order to ensure product molding accuracy and demoulding, the present invention provides a honeycomb sandwich composite material thin-layer radome and a molding method thereof;

[0063] This embodiment of the present invention can solve the above problems. The specific implementation method is as follows: the low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg combined with aramid paper (Nomex) honeycomb core used in the antenna cover of the present invention is used as the core material. Due to its high strength-to-weight ratio, good corrosion resistance and other favorable properties, the antenna cover can be used normally in the S band (2-4GHz), mechanical and temperature environments, thereby helping to improve the use environment range of the antenna cover;

[0064] And by using aramid paper honeycomb core as the core material, the honeycomb sandwich structure has a wide frequency band performance, good large incident angle performance, and stable structural strength;

[0065] The outer skin 1 and the honeycomb core 2, the inner skin 3, and the metal embedded parts 4 are all bonded using modified epoxy resin film (or modified cyanate film), which solves the bonding positioning problem of the metal embedded parts 4 and the composite material, and is beneficial to improving the stability of the bonding positioning of the antenna cover.

[0066] like Figure 5 The forming method of the thin layer antenna cover of the honeycomb sandwich composite material shown in the figure comprises the following steps:

[0067] Step 1: Mold assembly and mold processing: After wiping the release agent on the surface of the split mold, splice and fix the split mold, and then use a feeler gauge to check the mold gap to confirm that the mold surface and engraved lines are intact;

[0068] Step 2: Cutting and laying out the outer skin: Lay out the cut outer skin sheets according to the design requirements of the laying angle to form the outer skin 1, and then seal the bag for vacuum testing. The vacuum degree is required to drop no more than -0.04 bar within 5 minutes after being pumped to -0.950 bar.

[0069] Step 3: Curing the outer skin: Put the assembled and sealed outer skin 1 into a curing furnace, and after connecting the vacuum, cure it according to the set curing parameters;

[0070] Step 4: Honeycomb interlayer and metal inlay bonding: After cleaning the outer skin 1, the metal embedded parts 4, the honeycomb core 2 and the inner skin 3 are stacked and connected by a modified epoxy resin film (or a modified cyanate film), and then placed into a split mold, and the vacuum degree is tested after the bag is sealed;

[0071] Step 5: Inner skin curing: Put the sealed inner skin 3 into the curing furnace, and after connecting the vacuum, cure it according to the set curing parameters;

[0072] Step 6: Demolding of parts: After curing is completed, the split mold is disassembled and demoulded;

[0073] Step 7: Post-processing and painting: Use a CNC milling machine to inspect the product after processing, and then give the product a final paint job.

[0074] In order to solve the positioning of metal embedded parts and product demoulding problems, the thin-layer antenna cover of honeycomb sandwich composite materials is mainly formed into the following steps:

[0075] First, mold assembly and mold processing

[0076] If a new split mold is used, first remove the new mold oil seal and wipe the mold release agent on the mold surface to facilitate the demoulding of the radome after molding;

[0077] Subsequently, the side slider and the positioning side slider are connected from the bottom mold in turn through the positioning pins and bolts, and then the mold gap is checked with a feeler gauge to confirm that the mold surface and scale lines are intact to ensure that the mold can maintain sealing during the molding process, which is beneficial to avoid leakage of the modified epoxy resin film (or modified cyanate ester film) during the bonding process. At the same time, it is beneficial to ensure the stability of the added amount of modified epoxy resin film (or modified cyanate ester film) during the molding process, thereby ensuring the uniformity and stability of the raw materials used in the antenna cover molding process, and improving the stability of the antenna cover molding process.

[0078] Among them, Figure 4 As shown, as an optional embodiment, the split mold includes:

[0079] A bottom mold 5, on which a plurality of side sliding blocks 7 are arranged in a circumferential array;

[0080] A plurality of positioning side sliders 6 are arranged in a circular array and are spaced between adjacent side sliders 7. Positioning grooves 601 are symmetrically provided on the inner walls of the positioning side sliders 6.

[0081] The upper cover plate 8 is fixed to the top of all the positioning side sliders 6 and all the side sliders 7 by means of positioning pins and bolts, so as to connect and fix the bottom mold 5 and the positioning side sliders 6, the side sliders 7, and the upper cover plate 8;

[0082] The main purpose of setting up the split mold is to solve the positioning of the metal embedded parts of the product and the problem of product demoulding. The split mold is mainly composed of an upper cover plate 8 and a side slider 7, a positioning side slider 6, and a bottom mold 5. There are two ways to use the mold: one is to use it when the outer skin 1 of the antenna cover is formed, and the upper cover plate 8 is not used at this time; the other is to use it for the sandwich forming of the antenna cover honeycomb core 2, and the upper cover plate 8 is used at this time;

[0083] The split mold has a simple structure and conforms to ergonomics. The metal parts of the product are accurately positioned and easy to disassemble and demould. The product can be demoulded by removing the baffle and the side slider in sequence. The split mold combined with the antenna cover molding method can effectively improve product quality and molding cycle.

[0084] Second, cut and lay up the outer skin

[0085] A cutting drawing of the outer skin 1 is produced, for example, by using computer-aided design software. After the production is completed, the cut-out outer skin sheets are stacked according to the design requirements of the layering angle.

[0086] Wherein, as an optional embodiment, the total number of layers of the outer skin 1 is n layers of outer skin sheets, the outer skin sheets are low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepregs, connected by butt joint, the butt joint of the low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg is required to be less than or equal to 1mm, and then the release cloth-non-porous isolation membrane-air permeable felt are placed in sequence;

[0087] It should be noted that the n layers here are set according to needs, specifically n≥1 layer, and the thickness of a single layer of prepreg can be selected from different materials ranging from 0.05 mm to 0.8 mm.

[0088] After the outer skin 1 is initially laid up, a vacuum degree test is performed. The vacuum degree is required to not drop by more than -0.04 bar within 5 minutes after reaching -0.950 bar.

[0089] Third, the outer skin is cured

[0090] Put the assembled and sealed outer skin into the curing oven and connect the vacuum to cure it according to the curing parameters.

[0091] Fourth, perform honeycomb interlayer and metal inlay bonding

[0092] After the outer skin 1 is cleaned, dust and impurities on the surface of the outer skin 1 are cleaned during the molding process, thereby preventing dust and other impurities from causing adverse interference to subsequent bonding molding;

[0093] Subsequently, the metal embedded parts 4, the honeycomb core 2 and the inner skin 3 are connected by stacking with a modified epoxy resin film (or a modified cyanate ester film) and then placed into a split mold to assemble and connect the various structures of the radome to form the preliminary structure of the radome.

[0094] Wherein, as an optional embodiment, the inner skin 3 is a low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg having a total number of n layers;

[0095] It should be noted that the n layers here are set according to needs, specifically n≥1 layer, and the thickness of a single layer of prepreg can be selected from different materials ranging from 0.05mm to 0.8mm;

[0096] As an optional embodiment, the honeycomb interlayer and metal inlay bonding process specifically includes:

[0097] Prepare the honeycomb core 2 after the blocks are shaped and dried. The honeycomb core 2 can be divided into multiple blocks, which can be set according to the needs. For example, when a whole side surface of the antenna cover + a round bottom surface are used, a total of 2 honeycomb cores 2 are used. When the side surface and the bottom surface of the antenna cover are connected, it can be divided into 4-5 honeycomb cores 2; the honeycomb core 2 is cleaned and prepared in advance, so that the subsequent honeycomb core 2 can be directly used;

[0098] Use acetone to clean the bonding surface of the outer skin 1, and lay a modified epoxy resin film (or modified cyanate ester film) on the bonding surface;

[0099] Lay the honeycomb core 2 onto the modified epoxy resin film (or modified cyanate ester film) at a designated position, align and pre-draw, so that the modified epoxy resin film (or modified cyanate ester film) can bond the honeycomb core 2 and the outer skin 1;

[0100] Wrap the outer contour of the surface-treated metal embedded part 4 with a modified epoxy resin film (or a modified cyanate film) and a glass fiber fabric prepreg and place it in the positioning groove 601. The positioning groove 601 is positioned to make way for the metal embedded part 4 and locate the position of the metal embedded part 4.

[0101] Lay the modified epoxy resin film (or modified cyanate ester film) on the surface of the honeycomb core 2 and the metal embedded part 4, and then lay the inner skin 3;

[0102] After the metal embedded part 4 is positioned, the upper cover plate 8 is installed, and the metal embedded part 4, the upper cover plate 8 and the positioning side slider 6 are positioned by passing the positioning pin through the positioning hole, and finally the bag is sealed and the vacuum degree is tested;

[0103] The vacuum degree test here is the same as the vacuum degree test in the previous step, and the vacuum degree is required to not drop by more than -0.04 bar within 5 minutes after being pumped to -0.950 bar.

[0104] It should be noted that attention should be paid to the connection of the honeycomb core 2 at the honeycomb joints to avoid step differences caused by extrusion, so as to ensure the uniformity of the thickness of the honeycomb core 2.

[0105] It should be noted that the surface treatment of the metal embedded part 4 can be carried out in the following ways according to the requirements:

[0106] 1. Grinding + solvent wiping; 2. Acid etching; 3. Corona discharge; 4. Plasma treatment; 5. Laser treatment, etc.

[0107] Fifth, solidify the honeycomb interlayer and inner skin

[0108] The assembled and sealed inner skin 3 is placed in a curing furnace and connected to a vacuum oven for curing according to curing parameters.

[0109] The curing parameters of the outer skin 1 and the inner skin 3 are set according to the specific resin types selected for the outer skin 1 and the inner skin 3;

[0110] Specifically, for the radome that can meet the ambient temperature of -55℃-70℃, the curing parameters are:

[0111] Stage 1: Heating to 90°C at a rate of 2°C / min, and keeping warm for 30 minutes after the hysteresis reaches 90°C;

[0112] Stage 2: Heating at a rate of 2°C / min to 130°C, and keeping the temperature at 130°C for 120 min when the hysteresis reaches 130°C;

[0113] Stage 3: Cool down to below 60℃ and the mold is taken out of the curing oven;

[0114] For radomes with ambient temperatures ranging from -55°C to 150°C, the curing parameters are:

[0115] Stage 1: Heating to 130°C at a rate of 2°C / min, and keeping warm for 240 min after the hysteresis reaches 130°C;

[0116] Stage 2: Heating at a rate of 2°C / min to 177°C, and keeping the temperature at 177°C for 120 min when the hysteresis reaches 177°C;

[0117] Stage 3: Cool down to below 60°C and take the mold out of the curing oven.

[0118] Sixth, demoulding of parts

[0119] After removing the positioning pins and bolts on the upper cover plate 8 and the bottom mold 5 respectively, use a rubber hammer to gently knock down the side slider 7, and then remove the positioning side slider 6 in turn to complete the demoulding of the entire product.

[0120] Seventh, post-process and paint the demoulded radome

[0121] The products are inspected after machining using CNC milling machines, and then the products are given a final painting.

[0122] This invention mainly solves the problems of secondary curing molding and product demoulding of the antenna cover of a semi-enclosed rotating body. A split mold is designed to ensure smooth demoulding of the product, which not only improves production efficiency but also solves the demoulding problem.

[0123] Embodiment 1

[0124] For antenna covers with operating environment of -55℃-70℃.

[0125] 1. Mold assembly and mold processing

[0126] After wiping the release agent from the split mold, connect the side slider 7 and the positioning side slider 6 from the bottom mold 5 through the positioning pins and bolts in turn, and then use a feeler gauge to check the mold gap to confirm that the mold surface and engraved lines are intact.

[0127] 2. Cutting and laying out of outer skin 1

[0128] The cutting drawing of the outer skin layer is made by computer-aided design software, and the cut outer skin sheets are stacked according to the design requirements of the layer angle. The total number of layers is 3 layers of low-dielectric epoxy resin / glass fiber fabric prepreg, which are connected by butt-jointing. The butt joint is required to be ≤1mm. Release cloth, non-porous isolation film and breathable felt are placed in sequence, and the bag is sealed and the vacuum degree is tested. The vacuum degree is required to drop no more than -0.04bar within 5 minutes after being pumped to -0.950bar.

[0129] 3. Curing of outer skin 1

[0130] Place the assembled and sealed outer skin 1 into a curing oven, connect it to vacuum, and perform curing according to the following curing parameters:

[0131] Stage 1: Heating to 90°C at a rate of 2°C / min, and keeping warm for 30 minutes after the hysteresis reaches 90°C;

[0132] Stage 2: Heating at a rate of 2°C / min to 130°C, and keeping the temperature at 130°C for 120 min when the hysteresis reaches 130°C;

[0133] Stage 3: Cool down to below 60°C and take the mold out of the curing oven.

[0134] 4. Honeycomb sandwich and metal inlay bonding

[0135] Prepare the honeycomb core 2 that has been shaped and dried in blocks, use acetone to clean the bonding surface of the outer skin 1, lay the modified epoxy resin film on the bonding surface, and then lay the honeycomb core 2 on the modified epoxy resin film at the specified position, pay attention to the connection at the honeycomb joint, avoid the step difference caused by extrusion, so as to ensure the uniformity of the honeycomb thickness, and then pre-extract, and then wrap the outer contour of the metal embedded part 4 that has been surface treated with the modified epoxy resin film and the glass fiber fabric prepreg and put it into the positioning groove 601 of the positioning side slider 6, and then lay the modified epoxy resin film on the surface of the honeycomb core 2 and the metal embedded part 4, and then lay the inner skin 3, the inner skin 3 is a total of 3 layers of low dielectric epoxy resin / glass fiber fabric prepreg, and then install the upper cover plate 8, the positioning pin passes through the positioning hole to position the metal embedded part 4, the upper cover plate 8 and the positioning side slider 6 are positioned and fixed, and the bag is sealed according to the stripping cloth-porous isolation membrane-breathable felt and the vacuum degree is tested.

[0136] 5.Curing of honeycomb sandwich and inner skin 3

[0137] Put the assembled and sealed inner skin 3 into the curing oven, connect the vacuum, and cure according to the following curing parameters:

[0138] Stage 1: Heating to 90°C at a rate of 2°C / min, and keeping warm for 30 minutes after the hysteresis reaches 90°C;

[0139] Stage 2: Heating at a rate of 2°C / min to 130°C, and keeping the temperature at 130°C for 120 min when the hysteresis reaches 130°C;

[0140] Stage 3: Cool down to below 60°C and take the mold out of the curing oven.

[0141] 6. Part demoulding

[0142] After removing the positioning pins and bolts of the upper cover plate 8 and the bottom mold 5 respectively, use a rubber hammer to gently knock down the side slider 7, and then remove the positioning side slider 6 in turn to complete the demoulding of the entire product.

[0143] 7. Post-processing and painting

[0144] The products are inspected after machining using CNC milling machines, and then the products are given a final painting.

[0145] Embodiment 2

[0146] For antenna covers with operating environment of -55℃-150℃.

[0147] 1. Mold assembly and mold processing

[0148] After wiping the release agent from the split mold, connect the side slider 7 and the positioning side slider 6 from the bottom mold 5 through the positioning pins and bolts in turn, and then use a feeler gauge to check the mold gap to confirm that the mold surface and engraved lines are intact.

[0149] 2. Cutting and laying out of outer skin 1

[0150] The cutting drawing of the outer skin layer is made by computer-aided design software, and the cut outer skin pieces are stacked according to the design requirements of the layer angle. The total number of layers is 3 layers of cyanate / quartz fiber prepreg, which are connected by butt-jointing. The butt joint is required to be ≤1mm. Release cloth, non-porous isolation film and breathable felt are put in order, and then the bag is sealed and the vacuum degree is tested. The vacuum degree is required to drop no more than -0.04bar within 5 minutes after being pumped to -0.950bar.

[0151] 3. Curing of outer skin 1

[0152] Place the assembled and sealed outer skin 1 into a curing oven, connect it to vacuum, and perform curing according to the following curing parameters:

[0153] Stage 1: Heating to 130°C at a rate of 2°C / min, and keeping warm for 240 min after the hysteresis reaches 130°C;

[0154] Stage 2: Heating at a rate of 2°C / min to 177°C, and keeping the temperature at 177°C for 120 min when the hysteresis reaches 177°C;

[0155] Stage 3: Cool down to below 60°C and take the mold out of the curing oven.

[0156] 4. Honeycomb sandwich and metal inlay bonding

[0157] Prepare the honeycomb core 2 that has been shaped and dried in blocks, use acetone to clean the bonding surface of the outer skin 1, lay the modified cyanate ester adhesive film on the bonding surface, and then lay the honeycomb core 2 on the modified cyanate ester adhesive film at the specified position, pay attention to the connection at the honeycomb joint, avoid the step difference caused by extrusion, so as to ensure the uniformity of the honeycomb thickness, and then pre-extract, and then wrap the outer contour of the metal embedded part 4 that has been surface treated with the modified cyanate ester adhesive film and the glass fiber fabric prepreg and put it into the positioning groove 601 of the positioning side slider 6, and then lay the modified cyanate ester adhesive film on the surface of the honeycomb core 2 and the metal embedded part 4, and then lay the inner skin 3, the inner skin 3 is a total of 3 layers of low dielectric epoxy resin / glass fiber fabric prepreg, and then install the upper cover plate 8, the positioning pin passes through the positioning hole to position the metal embedded part 4, the upper cover plate 8 and the positioning side slider 6 are positioned and fixed, and the bag is sealed according to the stripping cloth-porous isolation membrane-breathable felt and the vacuum degree is tested.

[0158] 5.Curing of honeycomb sandwich and inner skin 3

[0159] Put the assembled and sealed inner skin 3 into the curing oven, connect the vacuum, and perform curing according to the following curing parameters:

[0160] Stage 1: Heating to 130°C at a rate of 2°C / min, and keeping warm for 240 min after the hysteresis reaches 130°C;

[0161] Stage 2: Heating at a rate of 2°C / min to 177°C, and keeping the temperature at 177°C for 120 min when the hysteresis reaches 177°C;

[0162] Stage 3: Cool down to below 60°C and take the mold out of the curing oven.

[0163] 6. Part demoulding

[0164] After removing the positioning pins and bolts of the upper cover plate 8 and the bottom mold 5 respectively, use a rubber hammer to gently knock down the side slider 7, and then remove the positioning side slider 6 in turn to complete the demoulding of the entire product.

[0165] 7. Post-processing and painting

[0166] The products are inspected after machining using CNC milling machines, and then the products are given a final painting.

[0167] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A thin layer antenna cover made of honeycomb sandwich composite material, comprising an outer skin (1), characterized in that: Also includes: The outer skin (1) is arranged in a hood shape; A plurality of honeycomb cores (2) are glued and arranged inside the hood-shaped outer skin (1); An inner skin (3) is glued and arranged inside the honeycomb core (2); A plurality of metal embedded parts (4) are arranged in a circular array and are glued and fixed to the outer side wall of the outer skin (1), and positioning holes are provided through the metal embedded parts (4); The outer skin (1) is bonded to the honeycomb core (2), the inner skin (3), and the metal embedded part (4) by using a modified epoxy resin film (or a modified cyanate film).

2. The thin-layer radome of honeycomb sandwich composite material according to claim 1, characterized in that: Also includes: The outer skin (1) and the inner skin (3) both use low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg as skin material.

3. The thin-layer radome of honeycomb sandwich composite material according to claim 2, characterized in that: Also includes: The honeycomb core (2) uses an aramid paper honeycomb core as core material.

4. A method for forming a thin layer antenna cover made of honeycomb sandwich composite material, applicable to the thin layer antenna cover made of honeycomb sandwich composite material as claimed in any one of claims 1 to 3, characterized in that: The molding method comprises the following steps: Step 1, mold assembly and mold processing: after wiping the release agent on the surface of the split mold, the split mold is spliced ​​and fixed, and then the mold gap is checked with a feeler gauge to confirm that the mold surface and the engraved lines are intact; Step 2, cutting and laying out the outer skin: Lay out the cut outer skin sheets according to the design requirements of the laying angle to form the outer skin (1), and then seal the bag for vacuum testing. The vacuum degree is required to drop by no more than -0.04 bar within 5 minutes after being pumped to -0.950 bar. Step 3: Curing the outer skin: placing the assembled and sealed outer skin (1) into a curing furnace, and curing it according to the set curing parameters after connecting the vacuum; Step 4: Honeycomb interlayer and metal inlay bonding: After cleaning the outer skin (1), the metal embedded parts (4) and the honeycomb core (2) and the inner skin (3) are connected by stacking with a modified epoxy resin film (or a modified cyanate film), and then placed into the split mold, and the vacuum degree is tested after the bag is sealed; Step 5, curing the inner skin: placing the sealed inner skin (3) into a curing furnace, and curing it according to the set curing parameters after connecting the vacuum; Step 6: demoulding parts: after curing is completed, the split mold is disassembled and demoulded; Step 7: Post-processing and painting: Use a CNC milling machine to inspect the product after processing, and then give the product a final paint job.

5. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 4, characterized in that: The split mold comprises: A bottom mold (5), wherein a plurality of side sliding blocks (7) are arranged in a circular array on the bottom mold (5); A plurality of positioning side sliders (6) are arranged in a circular array and are spaced apart between adjacent side sliders (7), and positioning grooves (601) are symmetrically provided on the inner walls of the positioning side sliders (6); The upper cover plate (8) is fixed to the top of all the positioning side sliders (6) and all the side sliders (7) by means of positioning pins and bolts, so as to connect and fix the bottom mold (5) and the positioning side sliders (6), the side sliders (7) and the upper cover plate (8).

6. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 5, characterized in that: The step 4 specifically includes: A1, symmetrically preparing the honeycomb core (2) after shaping and drying; A2, using acetone to clean the bonding surface of the outer skin (1), and laying a modified epoxy resin film (or a modified cyanate ester film) on the bonding surface; A3, laying the honeycomb core (2) on the modified epoxy resin film (or modified cyanate ester film) at a designated position, aligning and then pre-extracting; A4, wrapping the outer contour of the metal embedded part (4) that has been subjected to surface treatment with a modified epoxy resin film (or a modified cyanate ester film) and a glass fiber fabric prepreg and placing it in the positioning groove (601); A5, laying a modified epoxy resin film (or a modified cyanate ester film) on the surface of the honeycomb core (2) and the metal embedded part (4), and then laying the inner skin (3); A6. Install the upper cover plate (8), and position the metal embedded part (4), the upper cover plate (8), and the positioning side slider (6) by passing the positioning pin through the positioning hole. Finally, seal the bag and perform vacuum detection.

7. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 5, characterized in that: The curing parameters are set according to the specific resin types selected for the outer skin (1) and the inner skin (3).

8. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 6, characterized in that: The A3 step further includes: Attention should be paid to the connection of the honeycomb joints of the honeycomb core (2) to avoid step differences caused by extrusion, so as to ensure the uniformity of the thickness of the honeycomb core (2).

9. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 7, characterized in that: The ply angle design requirements in step 2 specifically include: The outer skin (1) has a total number of n outer skin sheets, the outer skin sheets are low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepregs, connected by butt joint, and then placed in sequence with a release cloth-a non-porous isolation membrane-a breathable felt; The low dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg has a joint requirement of less than or equal to 1 mm.

10. The method for forming a thin-layer antenna cover made of honeycomb sandwich composite material according to claim 7, characterized in that: The step 4 also includes: The inner skin (3) is a low-dielectric epoxy resin (or cyanate ester) / glass fiber fabric (or quartz fiber) prepreg material with a total number of n layers.

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