Forming method of S-shaped air inlet channel stress supercharging section

Abstract

The application discloses an S-shaped inlet duct stress supercharging section forming method in the technical field of aircrafts, which comprises the following steps: 1) taking out carbon fiber / epoxy resin prepreg; 2) cleaning the surface of a mold for use; 3) blanking; 4) carrying out inner skin pasting according to a layering sequence; 5) sending the workpiece into a hot pressing tank for curing, carrying out bag removal after curing and cooling, and then carrying out drilling and demolding; 6) polishing the surface of the inner skin and cleaning; 7) positioning foam and pasting a cap-shaped rib; 8) sending the workpiece into the hot pressing tank for curing, carrying out bag removal after curing and cooling; 9) extracting the bottom surface of a honeycomb core according to a numerical model, using a blanking machine to cut the honeycomb core of the same size, and then carrying out cutting and chamfering; 10) positioning the honeycomb core and preforming; 11) pasting the outer skin according to the layering sequence; and 12) sending the workpiece into the hot pressing tank for curing, carrying out demolding after curing and cooling, and the application guarantees the internal quality, profile and mechanical properties of the inlet duct.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material products, in particular to a forming method of S-shaped air inlet channel structure section. BACKGROUND

[0002] Carbon fiber reinforced resin matrix composite material has the advantages of high strength and high modulus, light weight, strong designability, etc. In recent years, carbon fiber composite material structural parts have been widely used in the fields of aerospace, weapon equipment, aircraft and ship.

[0003] The air inlet channel is a flow channel for the aircraft engine to suck in air, and is one of the five components of the aero-engine and the main component of the aircraft propulsion system. In recent years, how to realize high structural strength and low weight of the air inlet channel design and manufacturing has attracted continuous exploration of many engineering designers.

[0004] According to different structural functions, the air inlet channel is generally divided into 2-3 sections, such as the lip air inlet section, the stress plenum section, and the engine connection section. The so-called stress plenum section, as the name implies, is a section that realizes the deceleration and pressure increase of high-speed airflow, converts the kinetic energy of airflow into pressure energy, which means that it is also the section with the strongest airflow impact strength. Therefore, high requirements are put forward for the mechanical properties and aerodynamic shape of the part. In this case, the design and use of foam cap type ribs and honeycomb cores not only improve the stiffness of the part, but also meet the weight reduction demand of the air inlet channel component. However, due to the large curvature of the S-shaped air inlet channel and the relatively complex structure, it is difficult to form during manufacturing, and the foam and honeycomb core are prone to positioning deviation and debonding, etc. which seriously affect the internal quality, shape and mechanical properties of the air inlet channel. Therefore, it is important to study the forming method of the S-shaped sandwich structure air inlet channel for both foam and honeycomb core. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a forming method of an S-shaped air inlet channel stress plenum section, which solves the problems of difficult forming during manufacturing, positioning deviation and debonding of foam and honeycomb core due to the large curvature of the S-shaped air inlet channel and the relatively complex structure, and guarantees the internal quality, shape and mechanical properties of the air inlet channel.

[0006] The purpose of the present application is achieved as follows: a forming method of an S-shaped air inlet channel stress plenum section, which is assembled by splicing the upper and lower two half-plates integrally formed and cooperating with fasteners, the half-plates are all structured with inner skin, foam, cap type rib, honeycomb core and outer skin, and the forming method of the half-plate comprises the following steps:

[0007] Step 1) Take out the carbon fiber / epoxy resin prepreg from the cold storage, and cool it at room temperature before use;

[0008] Step 2) Clean the surface of the mold and wait for use;

[0009] Step 3) Use an automatic cutting machine to cut according to the designed layup diagram;

[0010] Step 4) According to the layup sequence, the inner skin is laid and pasted;

[0011] Step 5) Send the product into the autoclave for curing, and after cooling, the bag is removed;

[0012] Step 6) Install the drilling jig on the mold to turn up the edge of the product and then demold;

[0013] Step 7) Polish the surface of the inner skin and clean it up;

[0014] Step 8) Position the foam and lay the hat-shaped rib, use laser projection and clamping plate to assist positioning the foam position, the specific operation is as follows: first, cover the foam with adhesive film, vacuum and compact for 14-16 minutes, then use a laser projector to position the foam position, and lay 1 layer of adhesive film in the projection area, the laying area needs to be expanded by 15-20mm, pre-vacuum for 14-16 minutes, then place the foam according to the projection position of the foam, install the foam positioning clamping plate on the mold tool one by one, check the fit of the foam under the laser projection, confirm the position, remove the clamping plate, make a bag, install the clamping plate again after the bag is made, then connect the vacuum bag and pre-vacuum, pre-vacuum and compact for more than 30 minutes under the condition that the foam is fixed by the positioning clamping plate; remove the clamping plate after pre-vacuuming, lift the vacuum bag, turn on the projection, check the foam position, if the position has not shifted, start the next step of laying, otherwise the foam needs to be repositioned and bonded according to the above method, in addition, for the gap that cannot be compacted, use adhesive film to fill it and then pre-vacuum for 14-16 minutes, until there is no gap between the foam and the inner skin, for the torn foam and the edge with missing corners, use foaming glue to fill them and then pre-vacuum for 14-16 minutes; after positioning the foam, use carbon threads to make 1-3mm thin strips and fill them between the foam and the inner skin, then lay the hat-shaped rib according to the layup sequence and complete the bag making;

[0015] Step 9) Send the product into the autoclave for curing, and after cooling, the bag is removed;

[0016] Step 10) According to the numerical model, extract the bottom surface of the honeycomb core, use the cutting machine to cut the same size honeycomb core, then cut and chamfer;

[0017] Step 11) Position the honeycomb core and pre-form;

[0018] Step 12) Lay and paste the outer skin according to the layup sequence;

[0019] Step 13) Send the product into the autoclave for curing, and after cooling, demold and perform subsequent cutting, drilling, and inspection work.

[0020] Further, step 10) specifically comprises: according to the honeycomb core direction in the numerical model, the size of the honeycomb core, cutting out a demolding cloth of the same size with a cutting machine, cutting out the honeycomb core according to the demolding cloth, then pasting the demolding cloth on a hard backing plate, cutting out a corresponding shape backing plate, pasting glue around the backing plate and pasting the honeycomb core thereon, polishing the edges of the honeycomb core according to the chamfer angle required by the honeycomb core in the numerical model, measuring the angle of the honeycomb core while polishing to ensure that the angle deviation is controlled within ±3°, after the chamfering of the honeycomb core is completed, cleaning the cells; and cleaning the surface of the honeycomb core, wrapping the honeycomb core with peelable cloth and air-permeable felt in turn, placing it in an oven at 70±5℃ for 1h, then sealing the honeycomb core in a sealed bag and transporting it to a clean room for use.

[0021] Further, step 11) specifically comprises: laying 1 layer of special adhesive film between the inner skin and the honeycomb core positioning, laying corresponding special adhesive film in other areas, the adhesive film is overlapped by 2-4mm, then vacuumizing and compacting for 14-16min, then placing the honeycomb core on the adhesive film, using foaming glue to bond at the joint of the honeycomb core, the joint needs to be trimmed and aligned, for the gaps that cannot be compacted, use adhesive film to fill in and then pre-vacuum for 14-16min until there is no gap between the honeycomb core and the inner skin, for the torn honeycomb core and the edge angle defect, use foaming glue to fill in and then pre-vacuum for 14-16min; then put the workpiece into the tank for honeycomb core preforming, after taking out of the tank and unpacking, use air grinder to polish the honeycomb core and foaming glue that are higher than the hat-shaped rib area to be flat and smooth, for the recess between the honeycomb core and the hat-shaped rib, fill in foaming glue again for preforming, so that the honeycomb core and the hat-shaped rib are basically smooth without height difference.

[0022] Further, step 4) specifically comprises: first, laying the sacrificial layer at the edge folding position, then pre-vacuumizing, then laying the cut pre-impregnated material according to the layering sequence, layering ratio and layering direction in the effective area of the mold, pre-vacuumizing for 14-16min after the first layer of fabric is laid, placing the prepared carbon twist wire at the two straight angles and the two side R angles for transition, the twist wire can be overlapped when the length is not enough; the overlap width of the first layer of fabric is 20mm, except for laying and compacting the first layer of pre-impregnated material once, vacuumizing and compacting once after laying and compacting four layers of pre-impregnated material each time, and the compacting time is more than 15min each time, cold pressing and pre-compacting after half of the material sheet is laid.

[0023] Further, the curing process of step 9) and step 13) is as follows:

[0024] Vacuumizing at room temperature, the vacuum degree is not less than 0.092MPa, and the workpiece is put into the tank for curing after cold pressure test;

[0025] Rising the temperature to 125±5℃ at room temperature, the rising rate is 1.0-2.0℃ / min, the medium temperature is set to 130℃, when the fastest rising thermocouple rises to 40℃, start pressurizing until 0.2MPa starts to hold pressure;

[0026] When the slowest thermocouple is warmed up to 120℃ and kept for 120-130 minutes;

[0027] After cooling down to below 80℃ at a rate of no more than 2℃ / min, the pressure is removed, and when the temperature of the fastest cooling thermocouple is reduced to below 60℃, the tank is opened.

[0028] Further, step 12 specifically includes: according to the design requirements, the outer skin is laid, after the first layer is laid, a pre-exhaustion of 14-16 minutes is carried out, then the next layer is laid, and finally a layer of Tedlar waterproof film is laid in the honeycomb core area, with an overlap of 2-4 mm, and the pre-exhaustion time is more than 2 hours; the pieces of outer skin are overlapped, and the overlap length is 24-26 mm; the joint positions are staggered layer by layer.

[0029] The present application mainly realizes the successful implementation of the related process operation which is difficult in the manufacturing process of the foam+honeycomb core sandwich structure section area, and the specific principle is as follows:

[0030] Due to the large curvature of the air inlet channel profile and the large laying area, as the number of pieces increases, the role of the pure vacuum pump (≤0.1Mpa) pressure will be greatly weakened, and the interlayer of these areas may still have the problems of bridging and wrinkling. The cold pressing pre-solidification method is to place the workpiece in a hot press tank and apply ≥0.1MPa pressure at low temperature or room temperature, which can assist in compacting the pieces that cannot be compacted by the vacuum pump through high pressure. Moreover, due to the large pressure applied by the hot press tank, the R angle and bending area can be filled with raw silicone to flatten the area and reduce the risk of bag explosion.

[0031] The use of carbon twisting wire can avoid the formation of bridging at the R angle during subsequent laying process. After the first layer of plain fabric with good ductility and easy to lay is laid, the pre-impregnated carbon twisting wire obtained by pressing the special twisting wire tool according to different R angle sizes is used to fill the four edge R area, so that the piece can pass through this area smoothly when laying, improving the laying operability and reducing the risk of R angle bridging and delamination.

[0032] Since the position of the air inlet foam not only affects the mechanical strength of the air inlet channel and the butt joint of the upper and lower section foam ribs, but also the area outside the cap-shaped rib is the honeycomb core, the offset of the foam will directly affect the size and position of the honeycomb core, so the accuracy of the foam position is very important; this process uses laser projection + card board auxiliary positioning method to position the foam position, which can perform two-way reference checking and checking the position offset before and after pre-exhaustion.

[0033] After the hat-shaped rib is formed, the flange thereof will form a variable-thickness lost layer area on the skin, which causes the honeycomb core placed between the hat-shaped ribs to be higher on four sides, and for this case, the honeycomb core height needs to be trimmed, and if the honeycomb core is processed from the bottom, due to the large curvature of the air inlet channel itself, the hat-shaped ribs are more, and the R angles of the flanges after forming are not the same, and it is difficult to adapt to the chamfering one by one, and it takes a long time, and after chamfering, the gap between the bottom surface of the honeycomb core and the skin and the hat-shaped rib may be too large, or multiple bonding verification is needed, otherwise the bonding strength of the product will be low. The method of preforming the honeycomb core and chamfering the front surface can be used to process the specific situation according to the upper surface after the honeycomb core is preformed. For the areas of the honeycomb core height, the foam glue overflow and the vacancy, the operation of using more repair and less repair is used to make the honeycomb core and the hat-shaped rib basically smooth and without height difference, so as to ensure the flatness of the surface of the outer skin, reduce the risk of debonding of the honeycomb core and ensure the outer shape of the outer skin.

[0034] In addition, when this section is matched with the next section of the air inlet channel, the bonding area will be polished and repaired, which will cause the fiber to break and affect the strength, and also affect the internal aerodynamic surface. In the early stage of layer design and mold design, a sacrificial layer design and mold milling surface processing compensation are specially added to the polishing area in the later stage, so as to ensure that there is no step difference between the internal surface of the air inlet lip section of the air inlet channel after polishing and the next section after assembly.

[0035] Compared with the prior art, the beneficial effects of the present application are:

[0036] 1) The method of inner skin forming, hat-shaped rib forming, honeycomb core + outer skin one-time forming is adopted, which can ensure the accurate positioning of foam, the bonding strength of honeycomb core and skin, meet the mechanical properties of the product, effectively reduce the weight of the product, improve the production efficiency and save the production cost;

[0037] 2) The hot press tank process is adopted to reduce the porosity of the composite material and improve the structural strength;

[0038] 3) The method of cold pressing and pre-solidification is adopted, and the product is pre-compacted every certain thickness of layer, so as to avoid the situations of un-compacted product, wrinkle, bridging, un-solidified internal resin and the like caused by one-time over-thick layer of prepreg, and ensure the internal quality of the product;

[0039] 4) The carbon twisted wire is used to fill the right angle area of the flange, so that the material sheet can be smoothly laid when laying in the right angle area, the layer operation is improved, and the risk of bridging and delamination in the right angle area is reduced;

[0040] 5) The foam positioning method combining laser projection and card board tool fixing is adopted to accurately position the foam, avoid the mechanical strength of the air inlet channel and the butt joint of the upper and lower section foam ribs caused by the deviation of the foam, and solve the size and position deviation problems of the area outside the hat-shaped rib.

[0041] 6) In the placement of the honeycomb core between the skin and the hat-shaped rib, the problem of the raised four edges of the honeycomb core after placement is solved by using the method of pre-solidification + front chamfer transition, which avoids the problems of chamfering the bottom of the honeycomb core one by one, and the low bonding strength caused by the large gap between the chamfered bottom surface of the honeycomb core and the skin and the hat-shaped rib, and the need for multiple bonding verification, etc., while ensuring the molding quality, reducing the operation difficulty, improving the production efficiency and saving the production cost;

[0042] 7) In order to avoid the fiber breakage caused by polishing when the section is matched with other sections, a sacrificial layer area is added to the polishing area in the later stage, and the corresponding position of the mold is milled to compensate, so as to ensure that there is no step difference between the internal profile of the section after polishing and the front and rear sections after assembly. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0044] Figure 1 The flowchart of the present application.

[0045] Figure 2 The structure diagram of the S-shaped intake port stress boosting section in the present application.

[0046] Figure 3 The upper half plate explosion diagram in the present application.

[0047] Figure 4 The schematic diagram of the inner skin after laying in the present application.

[0048] Figure 5 The laser positioning diagram of the foam in the present application.

[0049] Figure 6 The foam laser projection + clamping plate auxiliary mold diagram in the present application.

[0050] Figure 7 The clamping plate auxiliary mold structure diagram in the present application.

[0051] Figure 8 The pre-extraction diagram with clamping plate in the present application.

[0052] Figure 9 The foam installation diagram in the present application. Figure 4

[0053] ​Figure 10 As Figure 5 The schematic diagram of the hat-shaped rib in the middle.

[0054] Figure 11 The schematic diagram of the honeycomb core after positioning in the application.

[0055] Figure 12 The schematic diagram of the honeycomb core before and after polishing in the application.

[0056] Figure 13 As Figure 6 The schematic diagram of the honeycomb core in the middle.

[0057] Figure 14 The schematic diagram of the upper half plate after curing in the application.

[0058] Wherein, 100 upper half plate, 101 inner skin, 102 foam, 103 hat-shaped rib, 104 honeycomb core, 105 outer skin, 200 lower half plate, 300 card plate auxiliary mold. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0060] As Figures 2-3 The S-shaped intake port stress boosting section includes an upper half plate 100 and a lower half plate 200, which are assembled by cooperating with fasteners after splicing. An S-shaped intake port is formed between the upper half plate 100 and the lower half plate 200. The internal structures of the upper half plate 100 and the lower half plate 200 are the same, and both adopt an inner skin 101, a foam 102, a hat-shaped rib 103, a honeycomb core 104, and an outer skin 105 structure.

[0061] Since the upper half plate 100 and the lower half plate 200 have the same structure, the forming process of the upper half plate 100 will be described below, as shown in Figure 1 The forming process includes the following steps:

[0062] 1) Material taking

[0063] The carbon fiber / epoxy resin prepreg is taken out from the cold storage and cooled at room temperature for use.

[0064] 2) Mold processing

[0065] Anhydrous ethanol is poured onto clean wipes or rags to wipe off the mold surface dust, particulate matter and other excesses that affect the surface quality of the parts, keeping the mold surface smooth and clean. Confirm that the tool surface is undamaged, and the tool cutting line, excess line, coordinate system and other lines are clearly visible. Apply 3 coats of release agent on the working surface, with an interval of 15 minutes each time, and dry at room temperature for at least 30 minutes after completion of the construction.

[0066] 3) Prepreg blanking

[0067] Draw the profile of the intake port by Catia and Fibersim software. According to the principle that the seams of layers in the same direction should be staggered at least 25mm, use CAD drawing software to segment, encode, and sort each layer of the sheet, and make a blanking drawing. The blanking drawing is imported into the automatic blanking machine to cut the sheet accurately. The angle of the sheet can be guaranteed within 0.5°. After cutting, the sheets are sorted in order according to the layering sequence, and the sorted sheets are checked for completeness and damage.

[0068] 4) Preparation of twisted yarn

[0069] Cut the prepreg and the adhesive film into 24mm wide strips, then paste them together and roll them into a thin round bar. Then put it into the twisting tool and press it in the press at room temperature with a pressure of 10MPa for 30min to compact the prepreg twisted yarn.

[0070] 5) Prepreg laying

[0071] First, lay the sacrificial layer at the turning position, then pre-evacuate for 15min. Then, according to the layering sequence, layering ratio, layering direction, etc., lay the cut prepreg in the effective area of the mold. After the first layer of fabric is laid, pre-evacuate for 15min, and place the pre-prepared R5 carbon twisted yarn at the straight angle of the two end flanges and the R angle of the two sides for transition. If the length of the twisted yarn is not enough, it can be overlapped.

[0072] Note: The overlap width of the first layer of fabric is 20mm (to minimize the gap between each layer of prepreg, in addition to laying and compacting the first layer of prepreg once, vacuum and compact every four layers of prepreg after laying, and compact for more than 15min each time. To enhance the compaction effect, the sheet is laid to half and then cold-pressed for pre-compaction.

[0073] 6) Packaging

[0074] After the prepreg is laid, the auxiliary material is packaged according to the following figure.

[0075] 7) Curing

[0076] Transfer the mold to the effective area of the hot press tank, and after leak detection is qualified, cure according to the following curing parameters:

[0077] ① Vacuumize at room temperature, vacuum degree is not less than 0.092 MPa, put into tank for curing after cold pressure test;

[0078] ② Warm up to 125±5℃ at room temperature, warm-up rate is 1.0-2.0℃ / min, medium temperature is set to 130℃, when the fastest warm-up thermocouple rises to 40℃, start to pressurize, until 0.6 MPa, start to keep pressure;

[0079] ③ Keep warm for 120min-130min when the slowest thermocouple warms up to 120℃;

[0080] ④ When the temperature of the fastest cooling thermocouple drops to below 60℃, the tank can be opened, and the curing of the part is completed.

[0081] 8) Bag removal

[0082] When the mold temperature needs to be cooled to room temperature, the bag removal process can be performed. Open the vacuum bag and remove the auxiliary materials on the surface of the part, including air-permeable felt, release film, and peelable cloth. When cleaning the peelable cloth, handle it carefully to avoid tearing the surface fibers.

[0083] 9) Hole drilling

[0084] Place the bag-removed part together with the mold on the drilling jig, check whether the position of the drilling jig and the part is accurate after installation, and then drill holes on both sides of the flange.

[0085] 10) Inner skin 101 treatment

[0086] Use 50-180 mesh sandpaper to polish the entire inner skin 101 surface to increase the roughness and adhesion, and the obtained inner skin 101 is as shown in Figure 4 .

[0087] 11) Foam 102 treatment

[0088] First, use compressed air to clean the foam 102 surface of stains and other excess materials. Then use clean wiping paper to clean the foam 102 surface with anhydrous ethanol. After drying for 10 minutes, wrap the foam 102 with a peeling cloth and air-permeable felt in sequence and place it in an oven at 70℃ for 1 hour. Record the equipment code, drying temperature, start time of heat preservation, and end time of heat preservation. After the foam 102 is dried, wrap and seal the foam 102 with air-permeable felt and a sealed bag, take it out of the oven, and send it to a clean room. Remove the sealed bag, air-permeable felt, and peeling cloth, and use pressure-sensitive tape to remove the air-permeable felt debris for reuse.

[0089] 12) Foam 102 positioning

[0090] The position of the foam 102 not only affects the mechanical strength of the air inlet channel, the butt joint of the upper and lower section foam 102 ribs, but also the honeycomb core 104 outside the cap-shaped rib 103. The offset of the foam 102 will directly affect the size and position of the honeycomb core 104, so the accuracy of the position of the foam 102 is very important.

[0091] The process adopts the method of laser projection + card board auxiliary mold 300 to position the position of the foam 102, and the specific operation is as follows:

[0092] As shown in Figures 5-8 , first wrap the foam 102 with adhesive film, vacuum and compact for 15 minutes, then use a laser projector to locate the position of the cap-shaped rib 103, and lay 1 layer of adhesive film in the projection area, the laying area needs to be expanded by 15-20mm, and pre-vacuum for 15 minutes. Then, according to the projected position of the foam 102, place the foam 102 in turn. Install the foam 102 positioning card on the mold tool in turn, and review the adhesion of the foam 102 under the laser projection. After confirming that the position is correct, remove the card, make the bag, and then install the card again after the bag is made. Then connect the vacuum, arrange the pre-vacuum bag, and pre-vacuum and compact for more than 30 minutes under the condition that the foam 102 is fixed by the positioning card. After pre-vacuuming, remove the card, lift the vacuum bag, turn on the projection, and check the position of the foam 102. If the position is offset, start the next layer, otherwise pry the foam 102 and reposition and bond according to the above method. In addition, for the gap that cannot be compacted, use adhesive film to fill and then pre-vacuum for 15 minutes until there is no gap between the foam 102 and the inner skin 101; for the foam 102 tearing, edge angle (within the allowable range of inspection requirements), use foaming glue to fill and then pre-vacuum for 15 minutes, as shown in Figure 9 .

[0093] 13) Cap-shaped rib 103 forming

[0094] After positioning the foam 102, use carbon twisted wire to form a 2mm or so thin strip and fill between the foam 102 and the inner skin 101. Then, according to the layering sequence, lay the cap-shaped rib 103 sheet and complete the bag making. After laying the cap-shaped rib 103, as shown in Figure 10 .

[0095] 14) Curing

[0096] Transport the mold to the effective temperature area of the hot press tank, and after passing the leak detection, complete the curing of the part according to the following parameters:

[0097] ① Vacuum at room temperature, vacuum degree not less than 0.092MPa, after passing the cold pressure test, put into the tank for curing;

[0098] ②Ramp to 125 ± 5 °C at 1.0-2.0 °C / min, set the medium temperature to 130 °C, when the fastest heating thermocouple rises to 40 °C, start pressurizing, until 0.2 MPa starts to hold pressure;

[0099] ③When the slowest thermocouple is heated to 120 °C, hold for 120-130 min;

[0100] ④Cool to below 80 °C at a rate not greater than 2 °C / min, then remove the pressure, when the fastest cooling thermocouple temperature decreases to below 60 °C, the tank can be opened

[0101] 15) Honeycomb core 104 processing

[0102] According to the direction of the honeycomb core 104 in the numerical model, the size of the honeycomb core 104, use the cutting machine to cut out the same size release cloth, according to the release cloth to cut out the honeycomb core 104, then paste the release cloth on a hard backing plate, cut out the corresponding shape backing plate. Paste double-sided tape around the backing plate and stick the honeycomb core 104 on it. According to the chamfer angle required by the honeycomb core 104 in the numerical model, use the grinder to polish the edge of the honeycomb core 104, measure the angle of the honeycomb core 104 with the angle ruler while polishing, ensure that the angle deviation is controlled within ± 3°, meet the design requirement (± 5°). After chamfering the honeycomb core 104, clean the debris, particles and other excess materials in the cells with compressed air, and clean the surface of the honeycomb core 104 with anhydrous ethanol with a clean cloth. Wrap the honeycomb core 104 with peelable cloth and air-permeable felt in turn, place it in an oven at 70 ± 5 °C for 1 h, then seal it in a sealed bag and transfer it to a clean room.

[0103] 16) Honeycomb core 104 positioning

[0104] Lay 1 layer of skin, core adhesive film between the inner skin 101 and the honeycomb core 104 positioning, lay skin, prepreg adhesive film in other areas, the adhesive film overlaps 2-4 mm, then vacuumize and compact for 15 min, then place the honeycomb core 104 on the adhesive film, use foaming glue to bond at the joint of the honeycomb core 104, and trim and align the joint. For the gaps that cannot be compacted, use adhesive film to fill and then pre-vacuumize for 15 min, until there is no gap between the honeycomb core 104 and the inner skin 101. For the torn honeycomb core 104 and the edge angle (within the allowable range of inspection requirements), use foaming glue to fill and then pre-vacuumize for 15 min, as shown in Figure 11 .

[0105] 17) Honeycomb core 104 preforming

[0106] Preform the honeycomb core 104 in the tank, after unpacking, use an air grinder to polish the honeycomb core 104 and the foaming glue above the hat-shaped rib 103 area flat and smooth, as shown in Figure 12The recess between the honeycomb core 104 and the hat-shaped rib 103 is again filled with the preformed foam, making the recess between the honeycomb core 104 and the hat-shaped rib 103 substantially smooth and without height difference. The state of the honeycomb core 104 after being laid is shown in Fig. 6. Figure 13

[0107] 18) Laying of the outer skin 105

[0108] The outer skin 105 is laid according to the design requirements. After the first layer is laid, a pre-vacuum is applied for 15 minutes, and then the next layer is laid. Finally, a layer of Tedlar waterproof film is laid in the area of the honeycomb core 104, with an overlap of 2-4 mm. The pre-vacuum time is more than 2 hours. The pieces of the outer skin 105 are overlapped, and the overlap length is 25 mm. The joint positions are staggered layer by layer.

[0109] 19) Curing

[0110] The mold is transported to the effective temperature area of the autoclave, and after leak detection, the part is cured according to the following parameters:

[0111] ① Vacuum at room temperature, vacuum degree not less than 0.092 MPa, after passing the cold pressure test, the mold is cured in the autoclave;

[0112] ② The temperature is raised to 125±5℃ at room temperature, the heating rate is 1.0-2.0℃ / min, the medium temperature is set to 130℃, when the fastest heating thermocouple rises to 40℃, the pressure is applied, and the pressure is maintained until 0.2 MPa;

[0113] ③ When the slowest thermocouple is heated to 120℃, the temperature is maintained for 120-130 minutes;

[0114] ④ The temperature is lowered at a rate not greater than 2℃ / min to below 80℃, and then the pressure is removed, when the temperature of the fastest cooling thermocouple is lowered to below 60℃, the autoclave can be opened, as shown in Fig. 7. Figure 14

[0115] Finally, the cured and cooled part is demolded and then cut, drilled and inspected.

[0116] It should be particularly noted that when drilling holes in the composite part, a wooden block (or bakelite block) should be used to press against the back or other methods should be taken to prevent delamination at the hole exit.

[0117] The above examples are only used to help understand the method of the present application and its core idea. It should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.​​

Claims

1. A forming method of a S-shaped intake port forced supercharging section, the upper and lower two half-panels are assembled by splicing and fastening, and the half-panels are all of the structure of inner skin (101), foam (102), cap-shaped rib (103), honeycomb core (104), and outer skin (105), characterized in that, The forming method of the half-plate comprises the following steps: Step 1) Take out the carbon fiber / epoxy resin prepreg from the cold storage, and cool at room temperature before use; Step 2) Clean the surface of the mold and wait for use; Step 3) Use an automatic cutting machine to cut according to the designed layup diagram; Step 4) According to the layup sequence, the inner skin (101) is laid and pasted; Step 5) Put the workpiece into the autoclave for curing, and after cooling, the bag is removed; Step 6) Install the drilling jig on the mold to perform edge bending and punching of the workpiece, and then demold; Step 7) Polish the surface of the inner skin (101) and clean it; Step 8) Position the foam (102) and lay the hat-shaped rib (103), position the foam (102) using laser projection and clamping plate, and the specific operation is as follows: first, cover the foam (102) with adhesive film, vacuumize and compact for 14-16 minutes, then use a laser projector to position the foam (102), and lay 1 layer of adhesive film in the projection area, the laying area needs to be expanded by 15-20mm, and pre-vacuumize for 14-16 minutes, then place the foam (102) according to the projection position of the foam (102), and install the foam (102) positioning clamping plate on the mold tool one by one, check the fit of the foam (102) under the laser projection, and confirm that the position is correct, then remove the clamping plate, make a bag, install the clamping plate again after the bag is made, then connect the vacuum bag and pre-vacuumize for more than 30 minutes; after pre-vacuumizing, remove the clamping plate, open the vacuum bag, turn on the projection, and check the position of the foam (102), if the position does not shift, start the next step of laying, otherwise, pry open the foam (102), reposition and bond according to the above method, additionally, for the gaps that cannot be compacted, use adhesive film to fill them and then pre-vacuumize for 14-16 minutes until there is no gap between the foam (102) and the inner skin (101), and for the torn foam (102) and the edge corner, use foaming glue to fill them and then pre-vacuumize for 14-16 minutes; after positioning the foam (102), use carbon twisted wire to form 1-3mm thin strips and fill them between the foam (102) and the inner skin (101), then lay the hat-shaped rib (103) according to the layup sequence and complete the bag making; Step 9) Put the workpiece into the autoclave for curing, and after cooling, the bag is removed; Step 10) Extract the bottom surface of the honeycomb core (104) according to the numerical model, use a cutting machine to cut the same size honeycomb core (104), and then cut and chamfer; Step 11) Position the honeycomb core (104) and pre-form it; Step 12) Lay the outer skin (105) according to the layup sequence; Step 13) Put the workpiece into the autoclave for curing, and after cooling, demold and perform subsequent cutting, punching and inspection.

2. The method of claim 1, wherein the S-shaped intake passage force supercharging section is formed by a plurality of curved lines. Step 10) specifically includes: according to the direction of the cellular core (104) in the numerical model, the size of the cellular core (104), cutting out the same size release cloth with the cutting machine, cutting out the cellular core (104) according to the release cloth, then sticking the release cloth on the hard backing plate, cutting out the corresponding shape backing plate, sticking glue around the backing plate and sticking the cellular core (104) on it, grinding the edge of the cellular core (104) according to the chamfer angle required by the cellular core (104) in the numerical model, measuring the angle of the cellular core (104) while grinding to ensure that the angle deviation is controlled within ±3°, after the chamfering of the cellular core (104) is completed, clean the cells; and clean the surface of the cellular core (104), wrap the cellular core (104) with peelable cloth and air-permeable felt in turn, place it in an oven at 70±5℃ for 1h, then seal the cellular core (104) in a sealed bag and transfer it to a clean room for use.

3. The method of claim 1 or 2, wherein the S-shaped intake passage force supercharging section is formed by a plurality of curved lines. Step 11) specifically includes: laying 1 layer of special adhesive film between the inner skin (101) and the cellular core (104) positioning, other areas also lay corresponding special adhesive film, the adhesive film overlaps 2-4mm, then vacuumize and compact for 14-16min, then place the cellular core (104) on the adhesive film, use foaming glue to bond at the joint of the cellular core (104), the joint needs to be trimmed and aligned, for the gaps that cannot be compacted, use adhesive film to fill and then pre-vacuumize for 14-16min until there is no gap between the cellular core (104) and the inner skin (101), for the torn cellular core (104) and the edge of the missing angle, fill with foaming glue and then pre-vacuumize for 14-16min; then put the workpiece into the tank for cellular core (104) preforming, after taking out of the tank and unpacking, use air grinder to polish the cellular core (104), foaming glue and the area above the hat-shaped rib (103) to be flat and smooth, for the recess between the cellular core (104) and the hat-shaped rib (103), fill with foaming glue again for preforming, so that the cellular core (104) and the hat-shaped rib (103) are basically smooth and have no height difference.

4. The method of claim 1 or 2, wherein the S-shaped intake passage force supercharging section is formed by a plurality of curved lines. Step 4) specifically includes: first, lay the sacrificial layer at the edge folding position, then pre-vacuumize, then according to the layering sequence, layering ratio and layering direction, lay the cut pre-impregnated material on the effective area of the mold, pre-vacuumize for 14-16min after the first layer of fabric is laid, place the prepared carbon twist wire at the two straight angles and R angles on both sides for transition, the twist wire can be overlapped when the length is not enough; the overlap width of the first layer of fabric is 20mm, except for the first layer of pre-impregnated material, vacuumize and compact once every four layers of pre-impregnated material, and each time the compacting time is more than 15min, after the material sheet is laid to half, cold pressing is performed for pre-compaction.

5. The method of claim 1 or 2, wherein the S-shaped intake passage force supercharging section is formed by a plurality of curved lines. The curing process of step 9) and step 13) is as follows: Vacuumize at room temperature, the vacuum degree is not less than 0.092MPa, after cold pressing test, put into the tank for curing; Warm up to 125±5℃ at room temperature, the warming rate is 1.0-2.0℃ / min, the medium temperature is set to 130℃, when the fastest warming thermocouple rises to 40℃, start pressurizing until 0.2MPa starts to hold pressure; When the slowest thermocouple rises to 120℃, hold for 120-130min. After the temperature is decreased to below 80°C at a rate of not more than 2°C / min, the pressure is released, and the can is opened when the temperature of the fastest thermocouple decreases to below 60°C.

6. The method of claim 1 or 2, wherein the S-shaped intake passage force supercharging section is formed by a method comprising: Step 12) specifically includes: according to the design requirements, the outer skin (105) is laid, after the first layer is laid, a pre-exhaustion of 14-16 min is carried out, then the next layer is laid, and finally a layer of Tedlar waterproof film is laid in the area of the honeycomb core (104), with an overlap of 2-4 mm, and the pre-exhaustion time is more than 2 h; the pieces of the outer skin (105) are overlapped, the overlap length is 24-26 mm, and the joint positions are staggered layer by layer.

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