Composite material rib box mold based on magnetic attraction guiding and using method of composite material rib box mold

Abstract

The invention relates to the technical field of composite material forming molds, and discloses a composite material rib box mold based on magnetic attraction guiding and a using method thereof.The using method comprises the following steps that mold movable blocks are moved to adjacent mold movable blocks, and the matched mold movable blocks are attracted and attached through strong magnetic patches; the guide pin is aligned with the guide hole and is combined with the guide hole, the mold movable block is pressed, and the guide pin is pushed along the guide hole; the forming raw materials are put into a cavity formed by pressing a mold loose piece; pressurizing, heating and curing the molding raw materials in a vacuum environment; and cooling and separating the mold loose piece. The invention aims to create a three-stage coordinated loading and unloading mechanism of magnetic attraction pre-fixing, mechanical fine positioning and jackscrew separation, so that the time and workload of mold loading and demolding are greatly saved, the problems of abrasion, insufficient pre-tightening force and the like of a traditional loading and unloading threaded hole in the mold are avoided, and the product forming precision is improved.

Description

Technical Field

[0001] This invention relates to the field of composite material molding die technology, specifically to a composite rib box die based on magnetic attraction guidance and its usage method. Background Technology

[0002] Carbon fiber composites, due to their high specific strength, high specific modulus, and excellent corrosion resistance, have become key materials for lightweighting in aerospace, automotive, and other fields. However, their molding process faces a dual contradiction between material properties and process requirements: the anisotropy of carbon fibers requires a strict match between the layup direction and the structural stress, but traditional wet manual layup is inefficient and lacks precision. This leads to low efficiency and severe electrode wear in the machining of complex components such as aero-engine blades using traditional electrical discharge machining (EDM), while laser cutting is prone to resin matrix decomposition due to heat accumulation, resulting in a heat-affected zone width of 0.3-0.5 mm and material strength loss. Furthermore, the demand for precision micro-pore machining and irregular curved surface forming in aerospace structural components creates a sharp contradiction with defects such as fiber delamination and burrs caused by machining. Taking carbon fiber pultruded sheets as an example, porosity / void defects significantly reduce interlaminar shear strength, compressive strength, and fatigue strength, while increasing hygroscopicity and accelerating crack initiation, severely restricting the full realization of material properties.

[0003] Current mainstream molding processes all have significant technical shortcomings: Resin transfer molding can achieve high resin utilization, but the mold must have high sealing and thermal conductivity, and complex structural parts require multiple trial moldings to adjust parameters; Pultrusion molding is limited by its shape limitation and is only suitable for simple structures such as rods and tubes, and is prone to defects such as cracks and bubbles during production; Although 3D printing technology can manufacture complex structures, it has poor material adaptability, and the tensile strength and modulus of carbon fiber reinforced thermoplastics (such as SLS and FDM processes) are lower than those of prepregs, and the equipment and material costs are several times higher than those of traditional processes, which limits its large-scale application in the aerospace field; Hand lay-up molding is entirely dependent on manual operation, resulting in low production efficiency and unstable quality.

[0004] Because traditional modular tooling often uses bolts to lock the movable blocks during positioning and locking, three common defects have arisen: each piece needs to be tightened individually during mold assembly and demolding, taking ≥10 minutes and consuming a significant amount of time and effort for tooling preparation personnel; repeated disassembly leads to wear on the threaded holes, with a lifespan typically <200 cycles, and damage to the threaded holes affects the tooling's service life and repair frequency; uneven bolt preload causes micro-displacement of the movable blocks, affecting part accuracy. Summary of the Invention

[0005] To address existing problems, this invention breaks away from the traditional bolt-locking approach and creates a three-tiered collaborative loading and unloading mechanism of "magnetic pre-fixing - mechanical precision positioning - set screw separation". This significantly saves time and workload in mold assembly and demolding, avoids problems such as wear of traditional loading and unloading threaded holes on the mold and insufficient pre-tightening force, and improves the precision of product molding.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] This invention provides a method for using a composite rib box mold based on magnetic attraction guidance, comprising the following steps: moving the mold block to an adjacent mold block, and the mating mold blocks are attracted and attached by strong magnetic patches; aligning the guide pin with the guide hole and engaging it, pressing the mold block, and pushing the guide pin along the guide hole; placing the molding material into the cavity formed by pressing the mold block; pressing and heating the molding material in a vacuum environment to solidify it; and separating the mold block after cooling.

[0008] As a further improvement of the present invention, the guide pin of the pressing mold block is pushed in along the guide hole, including the following steps: when fully pushed in, the gap between the mating surfaces of the mating mold blocks is less than or equal to 0.02 mm.

[0009] As a further improvement of the present invention, the method of pressurizing and heating the molding material in a vacuum environment includes the following steps: sealing the mold block containing the molding material in a vacuum bag.

[0010] As a further improvement of the present invention, the cooling separation mold block includes the following steps: separating the mold block by screwing the set screw into the set screw hole or by inserting the mold opening tool into the mold opening groove.

[0011] As a further improvement of the present invention, the raw material for pressure and temperature curing in a vacuum environment includes the following steps: maintaining the temperature and pressure in an environment of ≥125℃ and ≥0.3MPa for at least 120 minutes.

[0012] The present invention also provides a composite rib box mold based on magnetic attraction guidance, including a first mold block and a second mold block that cooperate with each other; one side of the first mold block is a first mating surface corresponding to the second mold block, a groove is provided on the first mating surface, and a guide pin is provided on the first mating surface outside the groove; one side of the second mold block is a second mating surface corresponding to the first mold block, a workpiece hole corresponding to the groove is provided on the second mating surface; a guide hole for cooperating with the guide pin is provided on the second mating surface; the second mold block is also provided with an ejector screw hole or a mold opening groove.

[0013] As a further improvement of the present invention, the first mold block or the second mold block is embedded with a strong magnetic patch, and the first mold block or the second mold block is made of ferromagnetic material.

[0014] As a further improvement of the present invention, the second mold block includes a first sub-mold block and a second sub-mold block, which are joined by a mortise and tenon structure.

[0015] As a further improvement of the present invention, the first mold block or the second mold block is made of steel.

[0016] As a further improvement of the present invention, the strong magnetic patch is made of neodymium iron boron material.

[0017] The present invention has the following beneficial effects: This method provides a way to use a composite rib box mold based on magnetic guidance. By combining magnetic attraction and guidance, the positioning and assembly process of the mold blocks is simplified. The magnetic attraction can quickly bring adjacent mold blocks into initial contact, while the cooperation of guide pins and guide holes further ensures the accuracy of mold block pressing, improving the efficiency and precision of mold assembly, and laying the foundation for accurate placement of subsequent molding materials and high-quality molding.

[0018] Preferably, when the guide pin is fully pushed in, the gap between the mating surfaces of the matching mold blocks should be less than or equal to 0.02 mm. This ensures good surface matching of the mold after pressing, thus providing good sealing and preventing leakage of the molding material or gas ingress during the curing process. It also helps improve the dimensional accuracy, surface quality, and aesthetics of the molded product, and reduces defects such as burrs and flash caused by excessive mold gaps.

[0019] Preferably, the mold block containing the molding material is vacuum-sealed, which effectively removes air and volatiles from the molding material in a vacuum environment, reducing internal porosity and defects, and improving the product's density and mechanical properties. Simultaneously, the vacuum environment ensures uniform pressure transmission during the pressurization and heating process, resulting in even heating and stress distribution throughout the molding material, further improving product quality.

[0020] Preferably, two methods are available for separating the mold movable block after cooling: either by screwing an ejector screw into the ejector screw hole or by inserting a mold opening tool into the mold opening groove. These two methods are simple and flexible to operate, allowing for the selection of the appropriate method based on actual conditions. This facilitates quick and easy separation of the mold movable block, improving mold utilization efficiency and disassembly convenience, and reducing the risk of damage to the mold and molded product during disassembly.

[0021] Preferably, the specific process parameters for pressurizing and curing the molding material in a vacuum environment are as follows: holding the material at a temperature greater than or equal to 180°C and greater than or equal to 0.6 MPa for at least 120 minutes. These parameters have been optimized and verified to ensure that the molding material is fully cured, enabling the product to achieve ideal mechanical and physical properties. Appropriate temperature, pressure, and holding time facilitate sufficient cross-linking and reaction between molecules, improving the product's strength, hardness, and heat resistance. This invention also provides a composite rib box mold based on magnetic guidance, including a first mold block and a second mold block that cooperate with each other, and their respective structural features. The groove and guide pin on the first mating surface cooperate with the workpiece hole and guide hole on the second mating surface, achieving precise positioning and assembly of the mold blocks. The setting of ejector screw holes or mold release grooves facilitates the separation of the mold blocks. The overall structural design is reasonable, improving the assembly accuracy, usage efficiency, and product quality of the mold.

[0022] Preferably, the first or second mold movable block is embedded with a strong magnetic patch made of ferromagnetic material. Utilizing the principle of magnetic attraction, the mold movable blocks can be quickly and accurately adsorbed and bonded together, improving the efficiency and stability of mold assembly. Simultaneously, this design facilitates mold disassembly and reuse, reducing errors and adjustment time during mold assembly.

[0023] Preferably, the second mold block is designed to include a first sub-mold block and a second sub-mold block, which are joined by a mortise and tenon structure. The mortise and tenon structure has good connection strength and stability, ensuring precise alignment and a secure connection between the sub-mold blocks, while also helping to improve the overall rigidity and deformation resistance of the mold. Furthermore, this split design facilitates mold processing, transportation, and maintenance, reducing mold manufacturing and operating costs.

[0024] Preferably, the first or second mold block is made of steel. Steel has high strength, high hardness, and good wear resistance, enabling it to withstand significant pressure and temperature changes during the pressurized and heated curing process, ensuring the shape stability and dimensional accuracy of the mold. Steel also has good thermal conductivity and sealing properties, making it suitable for pressurized heating. Furthermore, steel has a long service life, reducing the frequency of mold replacement and lowering production costs.

[0025] Preferred, the strong magnetic patch is made of neodymium iron boron material. Neodymium iron boron material has the advantages of high remanence, high coercivity and high magnetic energy product, which can provide strong magnetic attraction to ensure that the mold blocks are firmly attracted to each other. Even under the action of external force or vibration, they are not easy to separate, which improves the stability and reliability of mold assembly and helps to ensure the quality of molded products. Attached Figure Description

[0026] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and are not intended to specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a schematic diagram of a composite rib box mold structure based on magnetic attraction guidance in Example 1; Figure 2 This is a schematic diagram of the first mold block structure in Example 1; Figure 3 This is a step diagram illustrating the usage method of a composite rib box mold based on magnetic attraction guidance in Example 1; Figure 4 This is a schematic diagram of the second mold block structure in Example 2.

[0027] Among them, 1. First mold movable block; 2. Strong magnetic patch slot; 3. Strong magnetic patch; 4. Second mold movable block; 5. Guide pin; 6. Guide hole; 7. Ejector screw; 8. Ejector screw hole; 9. First sub-mold movable block; 10. Second sub-mold movable block; 11. Weight reduction hole engraving; 12. Positioning hole engraving. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0029] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Example 1 like Figure 1 As shown, this embodiment provides a composite rib box mold based on magnetic guidance, suitable for producing aircraft wing ribs, including a first mold block 1 and a second mold block 4 that cooperate with each other. Specifically, the dimensions of the first mold block 1 are 500mm × 100mm × 20mm, and the dimensions of the second mold block 4 are 500mm × 100mm × 40mm.

[0032] like Figure 2 As shown, one side of the first mold block 1 is the first mating surface corresponding to the second mold block 4. A groove is provided on the first mating surface, and a guide pin 5 is provided on the first mating surface outside the groove. A weight-reducing groove 11 and a positioning groove 12 are also provided in the groove. Specifically, the guide pin 5 is tapered, with a large end of Ø8h6 and a small end of Ø7.8h6, and a taper of 1:50; the inlet section of the guide hole 6 is Ø10H9, the outlet section is Ø8.1H7, and the depth is 15mm. The tapered surface fit automatically compensates for an initial alignment deviation of ±0.15mm.

[0033] One side of the second mold movable block 4 is a second mating surface corresponding to the first mold movable block 1. A workpiece hole corresponding to the groove is provided on the second mating surface; a guide hole 6 for engaging the guide pin 5 is provided on the second mating surface; the second mold movable block 4 is also provided with an ejector screw hole 8 or a mold opening groove. Specifically, the ejector screw hole 8 is an M8 threaded hole.

[0034] The first mold movable block 1 or the second mold movable block 4 is equipped with a strong magnetic patch 3. Specifically, the dimensions of the strong magnetic patch recess 2 on the first mold movable block 1 or the second mold movable block 4 are 20.02×50.02×3.01mm, and the dimensions of the strong magnetic patch 3 are 20×50×3mm. The contact surface of the strong magnetic patch 3 needs to be ground to a flatness of ≤0.02mm.

[0035] The first mold block 1 or the second mold block 4 is made of ferromagnetic material. Preferably, the ferromagnetic material is steel.

[0036] The strong magnetic patch 3 is made of neodymium iron boron material. The strong magnetic patch 3 can withstand a thermal environment of 180℃.

[0037] like Figure 3 As shown, this embodiment also provides a method for using a composite rib box mold based on magnetic guidance, including the following steps: Move the mold block to the adjacent mold block, and the matching mold blocks are attached by strong magnetic patch 3; align the guide pin 5 with the guide hole 6 and press the mold block together, and push the guide pin 5 along the guide hole 6; put the molding material into the cavity formed by pressing the mold block; press and heat the molding material in a vacuum environment to solidify the molding material; and separate the mold block after cooling.

[0038] Specifically, the pressing mold block, the guide pin 5 is pushed in along the guide hole 6, including the following steps: when fully pushed in, the gap between the mating surfaces of the mating mold blocks is less than or equal to 0.02mm.

[0039] Specifically, the process of pressurizing and heating the raw material in a vacuum environment to solidify it includes the following steps: sealing the mold block containing the raw material in a vacuum bag.

[0040] Specifically, the cooling and separation of the mold block includes the following steps: separating the mold block by screwing the set screw 7 into the set screw hole 8 or by inserting the mold opening tool into the mold opening groove.

[0041] The specific implementation process of this embodiment is as follows: Pre-assembly of movable blocks: Move the second mold block 4 to a distance of 3-5mm from the adjacent first mold block 1, and the strong magnetic patch 3 will automatically attract and pull it closer. Magnetic attraction causes the first mold block 1 and the second mold block 4 to initially fit together, with a fitting gap ≤0.1mm (measured by feeler gauge).

[0042] Precise positioning and locking: The guide pin 5 is inserted into the initial section of the guide hole 6 (initial deviation is allowed ±0.1mm). The second mold movable block 4 is pressed down, and the conical surface automatically corrects the offset, with the final fit clearance ≤0.02mm.

[0043] Composite material molding: 8 layers of carbon fiber prepreg are laid in the cavity of the assembly mold. After vacuum sealing, the product is placed in an autoclave for curing (at or above 180°C and above 0.6 MPa for 120 min). Specifically, the first stage involves heating from room temperature to 80°C, with a holding point at 80°C for 60 min; the second stage involves heating from 80°C to 130°C, with a holding point at 130°C for 120 min. The heating rate for the first stage is 1.5°C / min, and the heating rate for the second stage is 2°C / min, with a minimum heating rate not lower than 0.2°C / min.

[0044] Demolding with top screw 7: Allow the assembled mold cavity to cool naturally to room temperature; the cooling rate should not exceed 3°C / min.

[0045] Screw in M8 set screw 7 five turns to push the first mold block 1 and the second mold block 4 to separate; The set screw 7 generates a thrust, separating the first mold block 1 and the second mold block 4; Manually remove the first mold block 1 and the second mold block 4.

[0046] Example 2 The difference between this embodiment and Embodiment 1 is as follows: 1) The set screw hole 8 on the second mating surface is a countersunk hole.

[0047] like Figure 4 As shown, the set screw hole 8 on the second mating surface is a countersunk hole. The countersunk hole facilitates the accommodating of the screw head, preventing the protruding screw head from scratching other equipment or products on the production line. The countersunk hole also positions and guides the screw head, allowing for faster and more accurate alignment and screwing during installation. When disassembling the connector, the countersunk hole does not obstruct screw removal, facilitating maintenance and parts replacement. The countersunk hole forms a support for dirt or water films, preventing fluid from accidentally entering the set screw hole 8. Compared to through holes or other types of holes, countersunk holes reduce material usage and structural weight while meeting connection or functional requirements. Countersunk holes also optimize stress distribution, preventing excessive stress concentration around the hole and improving the overall strength and fatigue life of the structure.

[0048] Example 3 The difference between this embodiment and Embodiment 1 is as follows: 1) The second mold block 4 includes a first sub-mold block 9 and a second sub-mold block 10, which are joined by a mortise and tenon structure.

[0049] 2) The first mold block 1 or the second mold block 4 is made of 40Cr steel.

[0050] The second mold assembly 4 is designed to include the first sub-mold assembly 9 and the second sub-mold assembly 10, which are joined together by a mortise and tenon structure. The mortise and tenon structure provides excellent connection strength and stability, ensuring precise alignment and a secure connection between the sub-mold assemblies, while also improving the overall rigidity and deformation resistance of the mold. Furthermore, this modular design facilitates mold processing, transportation, and maintenance, reducing manufacturing and operating costs.

[0051] The first mold block 1 or the second mold block 4 is made of steel. Steel has high strength, high hardness, and good wear resistance, and can withstand large pressure and temperature changes during the pressurization and curing process, ensuring the shape stability and dimensional accuracy of the mold. At the same time, steel has a long service life, reducing the frequency of mold replacement and lowering production costs.

[0052] Example 4 The difference between this embodiment and Embodiment 1 is as follows: The process of pressurizing and heating the raw material in a vacuum environment includes the following steps: maintaining the temperature and pressure at 125°C and 0.3MPa for at least 120 minutes.

[0053] This embodiment provides a method for using a composite rib box mold based on magnetic attraction guidance, including the following steps: Move the mold block to the adjacent mold block, and the matching mold blocks are attached by strong magnetic patch 3; align the guide pin 5 with the guide hole 6 and press the mold block together, and push the guide pin 5 along the guide hole 6; put the molding material into the cavity formed by pressing the mold block; press and heat the molding material in a vacuum environment to solidify the molding material; and separate the mold block after cooling.

[0054] Specifically, the process of pressurizing and heating the raw material in a vacuum environment includes the following steps: maintaining the temperature and pressure at 125°C and 0.3MPa for at least 120 minutes.

[0055] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A method for using a composite rib box mold based on magnetic attraction guidance, characterized in that, Includes the following steps: Move the mold block to the adjacent mold block, and the matching mold blocks are attached by strong magnetic patches; The guide pin is aligned with the guide hole and engaged, pressing the mold movable block, and the guide pin is pushed in along the guide hole; The molding material is placed into the cavity formed by pressing the mold blocks together; Raw materials are cured and molded under pressure and temperature in a vacuum environment; After cooling, separate the mold blocks.

2. The method of using a composite rib box mold based on magnetic guidance according to claim 1, characterized in that, The movable block of the pressing mold is pushed in along the guide hole by the guide pin. The process includes the following steps: when fully inserted, the gap between the mating surfaces of the mating mold blocks is less than or equal to 0.02 mm.

3. The method of using a composite rib box mold based on magnetic guidance according to claim 1, characterized in that, The process of pressurizing and heating the raw material in a vacuum environment to solidify it includes the following steps: sealing the mold block containing the raw material in a vacuum bag.

4. The method of using a composite rib box mold based on magnetic guidance according to claim 1, characterized in that, The cooling and separation of the mold block includes the following steps: separating the mold block by screwing the set screw into the set screw hole or by inserting the mold opening tool into the mold opening groove.

5. The method of using a composite rib box mold based on magnetic guidance according to claim 1, characterized in that, The process of pressurizing and heating the raw material in a vacuum environment includes the following steps: maintaining the temperature and pressure at 125°C and 0.3MPa for at least 120 minutes.

6. A composite rib box mold based on magnetic guidance according to any one of claims 1-5, characterized in that, The device includes a first mold block and a second mold block that cooperate with each other; one side of the first mold block is a first mating surface corresponding to the second mold block, and a groove is provided on the first mating surface, and a guide pin is provided on the first mating surface outside the groove; one side of the second mold block is a second mating surface corresponding to the first mold block, and a workpiece hole corresponding to the groove is provided on the second mating surface; a guide hole for the guide pin is provided on the second mating surface; the second mold block is also provided with an ejector screw hole or a mold opening groove.

7. A composite rib box mold based on magnetic guidance according to claim 6, characterized in that, The first mold block or the second mold block is embedded with a strong magnetic patch, and the first mold block or the second mold block is made of ferromagnetic material.

8. A composite rib box mold based on magnetic attraction guidance according to claim 6, characterized in that, The second mold block includes a first sub-mold block and a second sub-mold block, which are joined together by a mortise and tenon structure.

9. A composite rib box mold based on magnetic attraction guidance according to claim 7, characterized in that, The first mold block or the second mold block is made of steel.

10. A composite rib box mold based on magnetic attraction guidance according to claim 7, characterized in that, The strong magnetic patch is made of neodymium iron boron material.

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