Molding system and molding method for a preformless composite core

Abstract

The present application relates to a kind of preformed composite core material forming system and forming method, it relates to composite core material technical field, including production mould, pouring bin, particle delivery device, liquid delivery device, vacuum pumping unit, piston part, air pressure driving device and ECT imaging system;Production mould includes upper die and lower die, the top of upper die has pouring port, the discharge port of pouring bin bottom is connected with pouring port, particle delivery device is connected with one side of pouring bin, and liquid delivery device is connected with the other side of pouring bin;Piston part is vertically slidingly assembled in pouring bin and is sealingly connected between the inner wall of pouring bin, vacuum pumping unit is connected with the side of pouring bin, air pressure driving device is connected with the top of pouring bin, and ECT imaging system is connected with production mould.The technical scheme of the present application can be formed with flexible fiberboard wrapped in the composite core material of local area of outer surface once, reduce mould cost and material turnover cost.

Description

Technical Field

[0001] This application relates to the field of composite core material technology, and in particular to a molding system and molding method for a preformless composite core material. Background Technology

[0002] There is a composite core material for fabric covering, mainly made of PET / PEA mixed resin. The manufacturing method is generally as follows: first, granular PET / PEA material is filled into the cavity of a first mold. Then, thermosetting liquid resin is filled into the cavity of the first mold through a transfer device. The overflow pipe on the first mold is in an overflow state, indicating that the cavity of the first mold is filled. When the first mold is heated, the thermosetting liquid resin fills and bonds the gaps between the PET / PEA materials to form a core material preform. Then, flexible glass fiber / carbon fiber boards are glued to the two opposite forming surfaces of a second mold and covered on the core material preform. After the resin cures, the glass fiber / carbon fiber boards are bonded and fixed to the core material preform to form a composite core material.

[0003] Regarding the aforementioned related technologies, the inventors believe that the following defects exist: When producing common fabric-covered composite core materials, two sets of molds need to be customized. This not only results in high mold costs and material turnover costs, but also in relatively complex manufacturing processes and low production efficiency. Summary of the Invention

[0004] This application provides a molding system and method for preformless composite core materials to improve the following technical problems: When producing common fabric-covered composite core materials, two sets of molds need to be customized. This not only results in high mold costs and material turnover costs, but also in relatively complex manufacturing processes and low production efficiency.

[0005] In a first aspect, this application provides a molding system for a preformless composite core material, employing the following technical solution: A molding system for a preformless composite core material includes a mold, an injection chamber, a particle conveying device, a liquid conveying device, a vacuum device, a piston, a pneumatic drive device, and an ECT imaging system. The mold is equipped with a heating module and an overflow pipe. The mold includes an upper mold and a lower mold. The bottom of the upper mold has an upper concave cavity, and the top of the lower mold has a lower concave cavity. The inner walls of the upper and lower concave cavities are used to bond flexible fiberboard. The edges of the upper mold and the lower mold are sealed together. The top of the upper mold has a filling port. The discharge port at the bottom of the filling chamber is connected to the filling port. The particle conveying device is connected to one side of the filling chamber and is used to convey foam particle material into the filling chamber. The liquid conveying device is connected to the other side of the filling chamber and is used to convey a thermosetting liquid resin-ferromagnetic powder mixture into the filling chamber. The piston is vertically slidably mounted inside the infusion chamber and is sealed to the inner wall of the infusion chamber. The vacuum pump is connected to the periphery of the infusion chamber and communicates with at least the chamber below the piston. The pneumatic drive device is connected to the top of the infusion chamber and is used to drive the piston to slide downward. The ECT imaging system is connected to the fabrication mold to monitor and display the distribution of thermosetting liquid resin and ferromagnetic powder inside the fabrication mold.

[0006] In one feasible technical solution of this application, a first flange is vertically provided on the bottom edge of the upper mold, and a second flange is vertically provided on the top edge of the lower mold, with a plurality of sealing rings sandwiched between the first flange and the second flange.

[0007] In one feasible technical solution of this application, the filling chamber includes a cylindrical chamber body, a connecting rigid pipe and a discharge valve. The top of the connecting rigid pipe is connected to the bottom of the cylindrical chamber body, the bottom of the connecting rigid pipe is connected to the filling port, and the discharge valve is installed on the connecting rigid pipe.

[0008] In one feasible technical solution of this application, the particle conveying device includes a storage bin, a first conveying pipe, and a first conveying valve. The storage bin is used to load foam particle material, the first conveying pipe is connected between the storage bin and the filling bin, and the first conveying valve is installed on the first conveying pipe.

[0009] In one feasible technical solution of this application, the liquid conveying device includes a mixing silo, a second conveying pipeline, and a second conveying valve. The mixing silo is used to load a thermosetting liquid resin-ferromagnetic powder mixture. The second conveying pipeline is connected between the mixing silo and the filling silo. The second conveying valve is installed on the second conveying pipeline.

[0010] In one feasible technical solution of this application, the vacuum pumping device includes a vacuum pump, a main pipe and multiple auxiliary pipes arranged vertically at intervals. One side of the main pipe is connected to one end of the multiple auxiliary pipes, the other side of the main pipe is connected to the vacuum pump, and the other end of the auxiliary pipes is connected to the injection chamber. A main valve is provided on the main pipe, and auxiliary valves are provided on the auxiliary pipes. The auxiliary pipes are connected to the chambers above and below the piston.

[0011] In one feasible technical solution of this application, the piston part includes a piston disc, a guide rod and a plurality of sealing rings. The guide rod passes through and is vertically slidably and sealingly connected to the top of the filling chamber. The piston disc is vertically connected to the bottom of the guide rod. The sealing rings are sleeved and fixed on the outer peripheral wall of the piston disc and abut against the inner peripheral wall of the filling chamber. The plurality of sealing rings are arranged vertically at intervals.

[0012] In one feasible technical solution of this application, the air compressor drive device includes an air compressor, an air compressor pipeline and an air compressor valve. One end of the air compressor pipeline is connected to the air compressor, the top of the filling chamber has multiple connection ports, the other end of the air compressor pipeline is connected to multiple connection ports, and the air compressor valve is installed on the air compressor pipeline.

[0013] In one feasible technical solution of this application, the ECT imaging system includes a processor, a display, multiple sets of electrodes for monitoring capacitance changes, and multiple Hall sensors. The processor is electrically connected to the display, all the electrodes, and all the Hall sensors. The electrodes are arranged around the outer wall of the mold and are made of copper foil or printed circuit boards. When the thermosetting liquid resin-ferromagnetic powder mixture flows in, it replaces the air and causes capacitance changes between the electrodes due to the difference in dielectric constants between the two. The processor reconstructs the resin distribution image of the cross-section of the mold using an inversion algorithm. The Hall sensors are used to detect the arrival time of the ferromagnetic powder at the corresponding position. The display is used to show the resin distribution image and the trigger leading edge time marker of the Hall sensors.

[0014] Secondly, this application provides a method for molding a preformless composite core material, employing the following technical solution: A method for molding a preformless composite core material, based on the above-mentioned molding system and including the following steps: Step 1: Start the vacuum device and turn on the particle conveying device. Fill the injection chamber with foam particle material by vacuuming until the cavity below the piston is filled and no more foam particle material can be sucked in. Then turn off the particle conveying device. The foam particle material is natural balsa wood particles or artificially made PU foam particles, PET foam particles, or PMI foam particles. The density of the foam particle material is 1 / 25 to 1 / 10 of the density of water. Step 2: Continue to start the vacuum device and turn on the liquid delivery device, inject an appropriate amount of thermosetting liquid resin-ferromagnetic powder mixture, start the air compressor drive device and drive the piston to descend, the particles are squeezed, and the resin penetrates into the gaps between the particles. The thermosetting liquid resin is epoxy resin, vinyl resin, PE engineering resin, PP engineering resin, or PVC engineering resin, and the ferromagnetic powder is magnetic powder, iron powder, or a mixture of magnetic powder and iron powder. Step 3: Turn off the vacuum pump and liquid delivery system; Step 4: According to the predetermined design, attach flexible fiberboard to the inner wall of the mold cavity. The flexible fiberboard is glass fiberboard or carbon fiberboard. Set up supports in the flat areas to prevent the flexible fiberboard on the inner wall of the upper mold from falling due to gravity and to promote the smooth diffusion of the raw material front to the low pressure area. Step 5: Turn on the air compressor drive and ensure that the injection chamber and the mold are connected. The piston continues to slide downwards, squeezing the foam particle material, thermosetting liquid resin and ferromagnetic powder mixture in the injection chamber into the mold cavity of the mold. Step 6: Observe the ECT imaging system, check the resin distribution image and the Hall sensor trigger front time marker to determine the various parts of the foam particle material-thermosetting liquid resin-ferromagnetic powder mixture entering the mold cavity; Step 7: Turn on the liquid delivery device until the overflow pipes at each preset location on the mold begin to overflow, then close the overflow pipes one by one, and then close the connection channel between the filling chamber and the mold. Step 8: Activate the heating module for mold making, and keep the mold inside the press at all times, maintaining a pressurized and sealed state. After cooling and solidification, demold to obtain a preformless composite core material.

[0015] In summary, this application includes at least one of the following beneficial technical effects: Using a single mold, a composite core material with a flexible fiberboard covering a local area of ​​the outer surface can be formed in one go, saving the cost of mold opening and maintenance, thereby reducing mold cost and material turnover cost. Moreover, the manufacturing process is also simpler and the production efficiency is higher. Furthermore, the resulting composite core material is extremely lightweight but has high structural strength, making it suitable for use as aircraft wing skin material or even other aerospace materials. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the molding system for the preformless composite core material according to an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 1. Mold making; 11. Upper mold; 111. Injection port; 12. Lower mold; 13. First flange; 14. Second flange; 15. Sealing ring; 2. Filling chamber; 21. Cylindrical chamber body; 211. Observation window; 22. Connecting rigid pipe; 23. Discharge valve; 3. Particle conveying device; 31. Storage silo; 32. First conveying pipeline; 33. First conveying valve; 4. Liquid conveying device; 41. Mixing silo; 42. Second conveying pipeline; 43. Second conveying valve; 5. Vacuum pumping device; 51. Vacuum pump; 52. Main pipeline; 53. Secondary pipeline; 54. Main valve; 55. Secondary valve; 6. Piston section; 61. Piston disc; 62. Guide rod; 63. Sealing ring; 7. Pneumatic drive unit; 71. Air compressor; 72. Pneumatic pipeline; 73. Pneumatic valve; 8. ECT imaging system; 81. Processor; 82. Display; 83. Electrode; 84. Hall sensor. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0021] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0024] This application discloses a molding system for a preformless composite core material. (Refer to...) Figure 1 The molding system for preformless composite core material includes a mold 1, an injection chamber 2, a particle conveying device 3, a liquid conveying device 4, a vacuum device 5, a piston 6, a pneumatic drive device 7, and an ECT imaging system 8. The mold 1 is equipped with a heating module and an overflow pipe. The mold includes an upper mold 11 and a lower mold 12. The bottom of the upper mold 11 has an upper concave cavity. Since the heating module and overflow pipe on the mold are existing technologies, and the actual positions of the heating module and overflow pipe can be adjusted according to the actual product, the heating module and overflow pipe are not specifically drawn in the accompanying drawings of this application. The top of the lower mold 12 has a lower concave cavity. The inner walls of the upper and lower concave cavities are used to bond flexible fiberboard. The edges of the upper mold 11 and the lower mold 12 are sealed together. The top of the upper mold 11 has a filling port 111. The discharge port at the bottom of the filling chamber 2 is connected to the filling port 111. The particle conveying device 3 is connected to one side of the filling chamber 2 and is used to convey foam particle material into the filling chamber 2. The liquid conveying device 4 is connected to the other side of the filling chamber 2 and is used to convey a thermosetting liquid resin-ferromagnetic powder mixture into the filling chamber 2. The piston part 6 is vertically slidably assembled in the infusion chamber 2 and is sealed to the inner wall of the infusion chamber 2. The vacuum pump 5 is connected to the periphery of the infusion chamber 2 and communicates with at least the chamber below the piston part 6. The pneumatic drive device 7 is connected to the top of the infusion chamber 2 and is used to drive the piston part 6 to slide downward. The ECT imaging system 8 is connected to the fabrication mold 1 to monitor and display the distribution of thermosetting liquid resin and ferromagnetic powder in the fabrication mold 1.

[0025] In this embodiment, in order to improve the sealing between the upper mold 11 and the lower mold 12 so that the product can be cured and formed, a first flange 13 is vertically provided on the bottom edge of the upper mold 11, and a second flange 14 is vertically provided on the top edge of the lower mold 12. A plurality of sealing rings 15 are sandwiched between the first flange 13 and the second flange 14.

[0026] In this embodiment, in order to facilitate the timely delivery and cutting off of the mixture, the filling chamber 2 includes a cylindrical chamber body 21, a connecting rigid pipe 22, and a discharge valve 23. The top of the connecting rigid pipe 22 is connected to the bottom of the cylindrical chamber body 21, and the bottom of the connecting rigid pipe 22 is connected to the filling port 111. The discharge valve 23 is installed on the connecting rigid pipe 22 and is an electrically controlled valve. The cylindrical chamber body 21 is provided with a transparent observation window. The design of the observation window makes it convenient for staff to observe the mixing of the internal materials from the outside at any time.

[0027] In this embodiment, the particle conveying device 3 includes a storage bin 31, a first conveying pipe 32, and a first conveying valve 33. The storage bin 31 is used to load foam particle material. The first conveying pipe 32 is connected between the storage bin 31 and the filling bin 2. The first conveying valve 33 is installed on the first conveying pipe 32 and is an electrically controlled valve. The liquid conveying device 4 includes a mixing bin 41, a second conveying pipe 42, and a second conveying valve 43. The mixing bin 41 is used to load a thermosetting liquid resin-ferromagnetic powder mixture. The second conveying pipe 42 is connected between the mixing bin 41 and the filling bin 2. The second conveying valve 43 is installed on the second conveying pipe 42 and is an electrically controlled valve.

[0028] The particle conveying device 3 and liquid conveying device 4 designed above have simple structures and can be used to convey solid particles and liquid mixtures respectively. In particular, the liquid conveying device 4 can be selected as a suction or discharge mode, which facilitates the recovery of some materials after overflow.

[0029] In this embodiment, the vacuuming device 5 includes a vacuum pump 51, a main pipe 52, and multiple auxiliary pipes 53 arranged vertically at intervals. One side of the main pipe 52 is connected to one end of each of the auxiliary pipes 53, and the other side of the main pipe 52 is connected to the vacuum pump 51. The other end of each auxiliary pipe 53 is connected to the filling chamber 2. A main valve 54 is installed on the main pipe 52, and auxiliary valves 55 are installed on the auxiliary pipes 53. Both the main valve 54 and the auxiliary valves 55 are electrically controlled valves. The auxiliary pipes 53 are connected to the chambers above and below the piston part 6. The vacuuming device 5 designed above has a simple structure and stable operation. It can quickly vacuum the filling chamber 2, thereby performing the "material suction" action, which is beneficial for the rapid and uniform mixing of the three materials—foam particle material, thermosetting liquid resin, and ferromagnetic powder—within the filling chamber 2.

[0030] At least one secondary pipe 53 is located above the piston section 6, and at least one secondary pipe 53 is located below the piston section 6. When it is necessary to drive the piston section 6 to slide upward, the secondary pipe 53 located above the piston section 6 remains connected and the secondary pipe 53 located below the piston section 6 remains closed. Then, the vacuum pump 51 is started to evacuate the upper cavity at the top of the filling chamber 2, so that the pressure above the piston section 6 is small, and the piston section 6 is driven to slide upward by the pressure difference.

[0031] In this embodiment, to improve the stability and sealing of the piston part 6 during vertical sliding, the piston part 6 includes a piston disc 61, a guide rod 62, and multiple sealing rings 63. The guide rod 62 passes through and is vertically slidably and sealingly connected to the top of the filling chamber 2. The piston disc 61 is vertically connected to the bottom of the guide rod 62. The sealing rings 63 are sleeved and fixed on the outer peripheral wall of the piston disc 61 and abut against the inner peripheral wall of the filling chamber 2. The multiple sealing rings 63 are arranged vertically at intervals. The piston disc 61 and the guide rod 62 are integrally molded Teflon plastic parts. Teflon plastic parts have multiple advantages such as high temperature resistance, corrosion resistance, and non-stick properties, higher chemical stability, and longer service life.

[0032] In this embodiment, the air compressor drive device 7 includes an air compressor 71, an air compressor pipe 72, and an air compressor valve 73. One end of the air compressor pipe 72 is connected to the air compressor 71, and the top of the filling chamber 2 has multiple connection ports. The other end of the air compressor pipe 72 is connected to multiple connection ports. The air compressor valve 73 is installed on the air compressor pipe 72 and is an electrically controlled valve. The air compressor drive device 7 designed above has a simple structure and stable operation. It can quickly increase the pressure in the chamber above the piston section 6 in the filling chamber 2, thereby driving the piston section 6 to squeeze downwards. This facilitates the rapid extrusion of the three materials—foam particle material, thermosetting liquid resin, and ferromagnetic powder—into the mold 1.

[0033] In this embodiment, the ECT imaging system 8 includes a processor 81, a display 82, multiple sets of electrodes 83 for monitoring capacitance changes, and multiple Hall sensors 84. The processor 81 is electrically connected to the display 82, all electrodes 83, and all Hall sensors 84. The electrodes 83 are arranged around the outer wall of the mold 1 and are made of copper foil or printed circuit boards. When the thermosetting liquid resin-ferromagnetic powder mixture flows in, it replaces the air and causes capacitance changes between the electrodes 83 due to the difference in dielectric constants between the two. The processor 81 reconstructs the resin distribution image of the cross-section of the mold using an inversion algorithm. The arrangement position of the Hall sensors 84 depends on the specific structure of the composite core material, that is, the Hall sensors 84 correspond to the key node positions of the composite core material. The Hall sensors 84 are used to detect the arrival time of the ferromagnetic powder at the corresponding positions. The display 82 is used to display the resin distribution image and the trigger leading edge time marker of the Hall sensors 84. The ECT imaging system 8 designed above can provide a two-dimensional image of the resin distribution in real time, and the Hall sensor 84 arranged at key positions can trigger the leading edge time marker. This dual-modal data fusion and monitoring mode will be more conducive to the staff to observe the conveying of various materials in the mold 1, thereby indirectly helping to control product quality.

[0034] This application also provides a molding method for a preformless composite core material, based on the above molding system and including the following steps: Step 1: Start the vacuum device 5 and turn on the particle conveying device 3. Fill the injection chamber 2 with foam particle material by vacuuming until the cavity below the piston part 6 is filled and no more foam particle material can be sucked in. Then turn off the particle conveying device 3. The foam particle material is natural balsa wood particles or artificially made PU foam particles, PET foam particles, or PMI foam particles. The density of the foam particle material is 1 / 25 to 1 / 10 of the density of water. Step 2: Continue to start the vacuum device 5 and turn on the liquid delivery device 4, inject an appropriate amount of thermosetting liquid resin-ferromagnetic powder mixture, start the air pressure drive device 7 and drive the piston part 6 to descend, the particles are squeezed, and the resin penetrates into the gaps between the particles. The thermosetting liquid resin is epoxy resin, vinyl resin, PE engineering resin, PP engineering resin, PVC engineering resin, and the ferromagnetic powder is magnetic powder, iron powder, or a mixture of magnetic powder and iron powder. Step 3: Turn off the vacuum pumping device 5 and the liquid delivery device 4; Step 4: According to the predetermined design, a flexible fiberboard is attached to the inner wall of the mold cavity of mold 1. The flexible fiberboard is a glass fiberboard or a carbon fiberboard. Supports are set in the flat areas with larger areas to prevent the flexible fiberboard on the inner wall of the upper mold 11 from falling due to gravity, and to promote the smooth diffusion of the raw material front to the low pressure area. Step 5: Turn on the air compressor drive device 7 and ensure that the injection chamber 2 and the mold 1 are connected. The piston part 6 continues to slide downward, squeezing the foam particle material, thermosetting liquid resin and ferromagnetic powder mixture in the injection chamber 2 into the mold cavity of the mold 1. Step 6: Observe the ECT imaging system 8, check the resin distribution image and the trigger front time marker of the Hall sensor 84, and determine the various parts of the foam particle material-thermosetting liquid resin-ferromagnetic powder mixture that have entered the mold cavity. Step 7: Turn on the liquid delivery device 4 until the overflow pipes at each preset location on the mold 1 begin to overflow, then close the overflow pipes one by one, and then close the connection channel between the filling chamber 2 and the mold 1. Step 8: Start the heating module of mold 1, and keep mold 1 in the press at all times, under pressure and sealed. After cooling and solidification, demold to obtain preformless composite core material.

[0035] The entire molding process is divided into the feeding and mixing stage, the in-mold preparation stage, the extrusion molding stage, and the curing and demolding stage. The opening and closing of each valve is automatically executed by the controller according to a preset sequence, specifically: (a) Feeding and mixing stage (corresponding to steps one to three) Foam particle inhalation: Start the vacuum pump 51, open the main valve 54 and the auxiliary valve 55 located below the piston section 6 (the auxiliary valve located above the piston section remains closed), and simultaneously open the first conveying valve 33, and close the second conveying valve 43, the discharge valve 23 and the air pressure valve 73.

[0036] The vacuum pump creates a vacuum in the chamber below the piston section 6 through the secondary pipe 53, forming a negative pressure that draws the foam particles in the storage bin 31 into the filling bin 2 via the first conveying pipe 32. When it is observed that the particles in the transparent observation window have filled the chamber below the piston section and can no longer be drawn in, the first conveying valve 33 is closed, and the vacuum pump continues to run for a short while to stabilize the negative pressure.

[0037] Resin-ferromagnetic powder mixture injection: Keep vacuum pump 51 running, with main valve 54 and lower auxiliary valve 55 still open. Close first delivery valve 33 and open second delivery valve 43. The thermosetting liquid resin-ferromagnetic powder mixture in mixing chamber 41 is drawn into injection chamber 2 through second delivery pipe 42 under negative pressure, where it is initially mixed with foam particles. The injection volume is controlled by preset time or liquid level sensor. Once the predetermined ratio is reached, second delivery valve 43 is closed.

[0038] Extrusion mixing: Close the main valve 54 and all auxiliary valves 55, and turn off the vacuum pump 51. Open the air compressor valve 73, start the air compressor 71, and introduce compressed air into the upper chamber of the piston section 6 through the air compressor pipe 72. This pushes the piston section 6 downwards slowly, applying pressure to the granule-resin-powder mixture below, allowing the resin to fully penetrate the gaps between the granules. During this process, the feed valve 23 remains closed to prevent the mixture from prematurely entering the mold. After extruding to the set pressure or displacement, close the air compressor valve 73 to complete the mixing stage.

[0039] (II) In-mold preparation stage (corresponding to step four) During this phase, the system is paused, and all feed valves (first conveying valve 33, second conveying valve 43), vacuum valves (main valve 54 and auxiliary valve 55), air compressor valve 73, and discharge valve 23 are closed. Operators attach flexible fiberboard to the inner walls of the upper and lower recesses of mold 1 according to the pre-designed plan, and set temporary supports in areas with larger, flat surfaces to prevent the upper mold fiberboard from falling off.

[0040] (III) Extrusion Molding Stage (corresponding to steps five to seven) The mixture is extruded into the mold: Ensure that the discharge valve 23 is closed, open the air compressor valve 73, and restart the air compressor 71 to pressurize the upper chamber of the piston section 6. After the pressure stabilizes, open the discharge valve 23 to connect the injection chamber 2 with the injection port 111 of the mold 1. The piston section 6 continues to slide downwards, forcing the mixture into the mold cavity through the connecting rigid pipe 22. During this process, all overflow pipe valves remain closed to facilitate the filling of the cavity with the mixture.

[0041] Online monitoring and feeding: Turn on the ECT imaging system 8 to observe in real time the resin distribution image reconstructed from the capacitance changes of electrode 83 and the trigger front time marker of Hall sensor 84. If the resin front does not reach the critical position as expected, the second delivery valve 43 can be briefly opened to add a small amount of resin mixture (at this time, the discharge valve 23 should be briefly closed to prevent backflow). After the ECT image shows that the resin has been evenly distributed to all parts of the mold cavity, turn off the ECT system (or keep it in standby mode).

[0042] Overflow confirmation and sealing: Keep the discharge valve 23 open and continue pressurizing the air valve 73. At the same time, open the second delivery valve 43 to continuously add a small amount of resin mixture into the injection chamber until the pre-set overflow pipes on the mold 1 begin to overflow (indicating that the mold cavity is completely filled). At this point, close each overflow pipe valve one by one, then close the discharge valve 23 to cut off the passage between the injection chamber and the mold, and finally close the air valve 73 and the air compressor 71.

[0043] (iv) Curing and demolding stage (corresponding to step eight) Close all valves (including the first conveying valve 33, the second conveying valve 43, the main valve 54, the auxiliary valve 55, the air compressor valve 73, the discharge valve 23, and all overflow valves) to ensure the mold is in a sealed and pressurized state. Start the heating module and heat the mold according to the preset temperature rise curve while maintaining the press pressure. After curing, cool to room temperature, open the sealing connection between the upper mold 11 and the lower mold 12 (remove the sealing ring 15 or loosen the locking mechanism), and demold to obtain the finished product.

[0044] Valve control logic summary: Vacuum pump related valves (main valve 54, auxiliary valve 55): open only when sucking in particles and resin, and close at other stages, and only open the auxiliary pipe 53 below the piston 6; if it is necessary to use vacuum to lift the piston, switch to open the upper auxiliary pipe.

[0045] First delivery valve 33: Opens only when foam particles are drawn in, and then remains closed.

[0046] Second delivery valve 43: Opens when drawing in resin and during subsequent replenishment overflow, and closes otherwise.

[0047] Feed valve 23: Opens during extrusion mixing and overflow replenishment, and closes during other processes (including feeding mixing, in-mold preparation, and curing).

[0048] Pneumatic valve 73: Opens during extrusion mixing, extrusion of the mixture, and overflow replenishment; closes otherwise.

[0049] Overflow valves: Open briefly only when the mold cavity is confirmed to be full, close them one by one immediately after overflow, and keep them closed during curing.

[0050] The beneficial technical effects of the molding system and molding method for the preformless composite core material in this application are roughly as follows: Using a single mold, a composite core material with a flexible fiberboard covering a local area of ​​the outer surface can be formed in one go, saving the cost of mold opening and maintenance, thereby reducing mold cost and material turnover cost. Moreover, the manufacturing process is also simpler and the production efficiency is higher. Furthermore, the resulting composite core material is extremely lightweight but has high structural strength, making it suitable for use as aircraft wing skin material or even other aerospace materials.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A molding system for a preformless composite core material, characterized in that, It includes a mold (1), a filling chamber (2), a particle conveying device (3), a liquid conveying device (4), a vacuum device (5), a piston (6), a pneumatic drive device (7), and an ECT imaging system (8); The manufacturing mold (1) has a built-in heating module and an overflow pipe, and the manufacturing mold includes an upper mold (11) and a lower mold (12). The bottom of the upper mold (11) has an upper concave cavity, and the top of the lower mold (12) has a lower concave cavity. The inner walls of the upper concave cavity and the lower concave cavity are used to bond flexible fiberboard. The edges of the upper mold (11) and the lower mold (12) are sealed together. The top of the upper mold (11) has a filling port (111). The discharge port at the bottom of the filling chamber (2) is connected to the filling port (111). The particle conveying device (3) is connected to one side of the filling chamber (2) and is used to convey foam particle material into the filling chamber (2). The liquid conveying device (4) is connected to the other side of the filling chamber (2) and is used to convey thermosetting liquid resin-ferromagnetic powder mixture into the filling chamber (2). The piston (6) is vertically slidably mounted in the infusion chamber (2) and is sealed to the inner wall of the infusion chamber (2). The vacuum device (5) is connected to the periphery of the infusion chamber (2) and is at least connected to the chamber below the piston (6). The pneumatic drive device (7) is connected to the top of the infusion chamber (2) and is used to drive the piston (6) to slide downward. The ECT imaging system (8) is connected to the fabrication mold (1) to monitor and display the distribution of thermosetting liquid resin and ferromagnetic powder in the fabrication mold (1). The ECT imaging system (8) includes a processor (81), a display (82), multiple sets of electrodes (83) for monitoring capacitance changes, and multiple Hall sensors (84). The processor (81) is electrically connected to the display (82), all the electrodes (83), and all the Hall sensors (84). The electrodes (83) are arranged around the outer wall of the mold (1) and are made of copper foil or printed circuit boards. When the thermosetting liquid resin-ferromagnetic powder mixture flows in, it replaces the air and causes capacitance changes between the electrodes (83) due to the difference in dielectric constants between the two. The processor (81) reconstructs the resin distribution image of the cross-section of the mold through an inversion algorithm. The Hall sensors (84) are used to detect the arrival time of the ferromagnetic powder at the corresponding position. The display (82) is used to display the resin distribution image and the triggering front time marker of the Hall sensors (84).

2. The molding system for preformless composite core material according to claim 1, characterized in that, The bottom edge of the upper mold (11) is vertically provided with a first flange (13), and the top edge of the lower mold (12) is vertically provided with a second flange (14). A plurality of sealing rings (15) are sandwiched between the first flange (13) and the second flange (14).

3. The molding system for preformless composite core material according to claim 1, characterized in that, The filling chamber (2) includes a cylindrical chamber body (21), a connecting hard pipe (22), and a discharge valve (23). The top of the connecting hard pipe (22) is connected to the bottom of the cylindrical chamber body (21), and the bottom of the connecting hard pipe (22) is connected to the filling port (111). The discharge valve (23) is installed on the connecting hard pipe (22).

4. The molding system for preformless composite core material according to claim 1, characterized in that, The particle conveying device (3) includes a storage bin (31), a first conveying pipe (32), and a first conveying valve (33). The storage bin (31) is used to load foam particle material. The first conveying pipe (32) is connected between the storage bin (31) and the filling bin (2). The first conveying valve (33) is installed on the first conveying pipe (32).

5. The molding system for preformless composite core material according to claim 1, characterized in that, The liquid conveying device (4) includes a mixing bin (41), a second conveying pipe (42), and a second conveying valve (43). The mixing bin (41) is used to load a thermosetting liquid resin-ferromagnetic powder mixture. The second conveying pipe (42) is connected between the mixing bin (41) and the filling bin (2). The second conveying valve (43) is installed on the second conveying pipe (42).

6. The molding system for preformless composite core material according to claim 1, characterized in that, The vacuum pumping device (5) includes a vacuum pump (51), a main pipe (52), and multiple auxiliary pipes (53) arranged vertically at intervals. One side of the main pipe (52) is connected to one end of the multiple auxiliary pipes (53), and the other side of the main pipe (52) is connected to the vacuum pump (51). The other end of the auxiliary pipes (53) is connected to the filling chamber (2). A main valve (54) is provided on the main pipe (52), and an auxiliary valve (55) is provided on the auxiliary pipes (53). The auxiliary pipes (53) are connected to the chambers above and below the piston part (6).

7. The molding system for preformless composite core material according to claim 1, characterized in that, The piston part (6) includes a piston disc (61), a guide rod (62) and a plurality of sealing rings (63). The guide rod (62) passes through and is vertically slidably and sealingly connected to the top of the filling chamber (2). The piston disc (61) is vertically connected to the bottom of the guide rod (62). The sealing rings (63) are sleeved and fixed on the outer peripheral wall of the piston disc (61) and abut against the inner peripheral wall of the filling chamber (2). The plurality of sealing rings (63) are arranged vertically at intervals.

8. The molding system for preformless composite core material according to claim 1, characterized in that, The air compressor drive device (7) includes an air compressor (71), an air compressor pipe (72), and an air compressor valve (73). One end of the air compressor pipe (72) is connected to the air compressor (71). The top of the filling chamber (2) has multiple connection ports. The other end of the air compressor pipe (72) is connected to multiple connection ports. The air compressor valve (73) is installed on the air compressor pipe (72).

9. A method for molding a preformless composite core material, characterized in that, The molding system based on any one of claims 1-8, comprising the following steps: Step 1: Start the vacuum device (5) and turn on the particle conveying device (3). Fill the injection chamber (2) with foam particle material by vacuuming until the cavity below the piston (6) is filled and no more foam particle material can be sucked in. Then turn off the particle conveying device (3). The foam particle material is natural balsa wood particles or artificially made PU foam particles, PET foam particles, and PMI foam particles. The density of the foam particle material is 1 / 25 to 1 / 10 of the density of water. Step 2: Continue to start the vacuum device (5) and turn on the liquid delivery device (4), inject an appropriate amount of thermosetting liquid resin-ferromagnetic powder mixture, start the air pressure drive device (7) and drive the piston part (6) down, the particles are squeezed, and the resin penetrates into the gap between the particles. The thermosetting liquid resin is epoxy resin or vinyl resin, and the ferromagnetic powder is magnetic powder, iron powder or magnetic powder-iron powder mixture. Step 3: Turn off the vacuum pump (5) and the liquid delivery device (4); Step 4: According to the predetermined design, a flexible fiberboard is pasted on the inner wall of the mold cavity of the mold (1). The flexible fiberboard is a glass fiberboard or a carbon fiberboard. Supports are set in the flat areas with large areas to prevent the flexible fiberboard on the inner wall of the upper mold (11) from falling due to gravity. Step 5: Turn on the air compressor drive device (7) and ensure that the injection chamber (2) and the mold (1) are connected. The piston (6) continues to slide downwards, squeezing the foam particle material, thermosetting liquid resin and ferromagnetic powder mixture in the injection chamber (2) into the mold cavity of the mold (1). Step 6: Observe the ECT imaging system (8), check the resin distribution image and the trigger front time marker of the Hall sensor (84), and determine the various parts of the foam particle material-thermosetting liquid resin-ferromagnetic powder mixture entering the mold cavity; Step 7: Turn on the liquid delivery device (4) until the overflow pipes at each preset location on the mold (1) begin to overflow, then close the overflow pipes one by one, and then close the connection channel between the filling chamber (2) and the mold (1); Step 8: Start the heating module of the mold (1), and the mold (1) is always placed in the press and kept under pressure and sealed. After cooling and solidification, demolding is performed to obtain the preformless composite core material.

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