A 3D printing unmanned aerial vehicle manufacturing method based on composite reinforcement

Abstract

The application belongs to the technical field of unmanned aerial vehicle manufacturing, and particularly relates to a 3D printing unmanned aerial vehicle manufacturing method based on composite material reinforcement, comprising the following steps: according to the forming size limitation of an FDM printer and the structural characteristics of a large-aspect-ratio unmanned aerial vehicle, the unmanned aerial vehicle body, the large-aspect-ratio wing and the operating control surface are split into blocks, positioning pin holes and limiting reference surfaces are reserved at the butt joint end surfaces of the split modules, a tool positioning reference structure is constructed, and a split three-dimensional printing model with a tool positioning reference is obtained. The application adopts a modular split design suitable for a small desktop FDM printer, splits the unmanned aerial vehicle body, the large-aspect-ratio wing and the operating control surface into multiple split modules, breaks through the limitation of the forming size of small equipment, and completes the base forming of the large-aspect-ratio unmanned aerial vehicle without large industrial printing equipment, greatly reduces the equipment investment and processing cost, shortens the forming cycle, and meets the requirements of rapid design iteration and small-batch production.

Description

Technical Field

[0001] This invention belongs to the field of drone manufacturing technology, and in particular relates to a method for manufacturing 3D-printed drones based on composite material reinforcement. Background Technology

[0002] High aspect ratio UAVs, with their high lift-to-drag ratio aerodynamic shape, possess excellent gliding performance and long endurance, and are widely used in high-altitude long-endurance reconnaissance, atmospheric environmental monitoring, geological exploration, forest fire prevention, and marine monitoring, making them a key research direction for low-altitude long-endurance aircraft. Compared to conventional fixed-wing UAVs, high aspect ratio UAVs have slender wings, making them more susceptible to elastic deformation and vibration coupling problems caused by airflow disturbances during flight. Therefore, they place higher demands on the overall structural rigidity, wing bending resistance, and aeroelastic stability.

[0003] 3D printing technology boasts advantages such as no need for mold making, short molding cycle, strong customization capabilities, and rapid design iteration. It can effectively solve the problems of long molding cycles, high costs, and difficult modification of traditional composite material mold molding processes. Currently, it has been gradually applied to the trial production and small-batch production of small and medium-sized drones. Existing low-cost 3D printed drones mostly use general-purpose PLA resin materials for one-piece printing. However, PLA materials themselves have inherent defects such as low modulus, poor rigidity, and weak interlayer bonding strength. When this process is applied to the manufacturing of high aspect ratio drones, the formed wings are prone to bending deformation and wing flutter during flight, causing rigid-elastic coupling vibration. In severe cases, this can lead to wing cracking and structural disintegration, greatly limiting the flight speed, cruising altitude, and operational life of 3D printed high aspect ratio drones.

[0004] Existing manufacturing processes still have several key shortcomings: First, the ultra-long wings of high aspect ratio UAVs cannot be adapted to the one-piece molding of small desktop printers. Conventional split printing solutions do not take into account the integrated design of control surfaces and tooling positioning benchmarks, resulting in poor precision in manual assembly, large gaps between joints, and insufficient structural rigidity after gluing. Second, the bending and torsional stiffness of pure PLA printed substrates is insufficient, which cannot effectively suppress aeroelastic vibrations caused by high-altitude airflow disturbances, resulting in poor structural reliability. Third, traditional composite reinforcement for 3D printed structures mostly adopts thermo-press curing processes, which are highly dependent on equipment, have cumbersome procedures, high mass production costs, and poor lightweighting effects. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned technical problems by providing a method for manufacturing 3D-printed drones based on composite material reinforcement.

[0006] In view of this, the present invention provides a method for manufacturing a 3D-printed drone based on composite material reinforcement, comprising the following steps: Based on the size limitations of FDM printers and the structural characteristics of high aspect ratio UAVs, the UAV fuselage, high aspect ratio wings, and control surfaces are divided into blocks. Positioning pin holes and limiting reference surfaces are reserved on the docking end faces of each block, and a tooling positioning reference structure is constructed to obtain a block 3D printed model with tooling positioning reference. The FDM (Fused Deposition Modeling) process is used, and PLA material is selected to print each separate module piece by piece. After printing, the support structure is removed, and the burrs and residual debris between layers on the module surface are polished and cleaned. The splicing and bonding areas of each modular unit and the glass fiber reinforcement areas are polished and cleaned. All the separate modules are fitted with positioning fixtures, and the positioning pin holes and limiting reference surfaces are matched and limited with the positioning structure of the fixtures. Aerospace structural adhesive is applied to the splicing surfaces of each module, and the fixtures are kept in a clamping state and cured at room temperature to complete the bonding and molding of the whole machine. Epoxy resin-based fiberglass prepreg is applied in layers to the module splicing gaps, wing leading edge, wing root transition area, upper and lower surfaces of the fuselage, and landing gear mounting base area of ​​the whole aircraft. After the application is completed, the entire structure is cured at room temperature. After curing, the positioning fixtures are removed, the whole machine is polished and repaired, and the operating control surfaces are installed to obtain a 3D-printed high aspect ratio UAV based on glass fiber composite material reinforcement.

[0007] Furthermore, the maximum external dimensions of the single-piece modular unit are less than 250mm×250mm×200mm, which is suitable for the printing range of a small desktop FDM printer; the single-sided wing is divided into 5 pieces, and the fuselage is divided into 6 pieces.

[0008] Furthermore, the conventional wing surface wall thickness is set to 0.4-0.6mm, while the wall thickness at the wing splicing position and wing root area is increased to 0.8-1.2mm, and the stress concentration sharp corners are rounded. Positioning holes with diameters of 10mm and 6mm are respectively provided at the front and rear beam positions of the docking ends of each wing segment, and positioning pin holes with diameters of 2-4mm are provided at the docking ends of each fuselage segment.

[0009] Furthermore, the specific FDM printing process parameters are as follows: printing temperature 195-210℃, printing speed 200-300mm / s, printing layer thickness 0.2mm, printing wall thickness 0.4mm, using grid-type filling with a filling density of 5%, and the thickness of the top layer and the bottom layer are both 0.4mm; the printing adopts a unidirectional layer-by-layer printing method, and the support structure is a tree-like support.

[0010] Furthermore, the polishing and cleaning process specifically involves: using 600-800 grit sandpaper to evenly and crosswise polish the adhesive area and the glass fiber reinforcement area; after polishing, wiping twice with anhydrous ethanol to thoroughly remove surface dust, grease and printing residue, and then placing it in a ventilated place at room temperature to air dry for 10-15 minutes.

[0011] Furthermore, the fuselage adopts a multi-point limiting structure, and each segment is fixed by positioning pin holes on each end face in conjunction with special clamps; the wings on both sides adopt an integral limiting structure, and each segment of the wing is sequentially threaded and aligned by two standard length carbon fiber hollow tubes with different outer diameters, and the wing is connected to the fuselage after splicing.

[0012] Furthermore, the aerospace structural adhesive is an epoxy-based high-strength structural adhesive with a layer thickness controlled at 0.1-0.2 mm; it is initially shaped by curing at room temperature for 2-4 hours under tooling clamping conditions, followed by complete curing by static standing for 12 hours.

[0013] Furthermore, the glass fiber prepreg is an epoxy resin-based unidirectional glass fiber prepreg with a single layer thickness of 0.1-0.2 mm; adjacent layers of prepreg are laid in a 0° / 90° cross-laying manner.

[0014] Furthermore, one layer of prepreg is applied to the seams of each module; an additional layer is applied to the leading edge area of ​​the wing and the transition area of ​​the wing root on top of the seam application; two layers are applied to the front and rear landing gear mounting base areas; after the overall application is completed, the surface is placed in a ventilated environment at room temperature for 24-36 hours to cure.

[0015] Furthermore, the installation steps of the control surface are as follows: the control surface is connected to the hinge plate using an optical axis to form a rotating pair, and the hinge plate is inserted into the corresponding wing groove and then fixed with screws.

[0016] The beneficial effects of this invention are: This invention adopts a modular design adapted to small desktop FDM printers, which breaks down the UAV fuselage, high aspect ratio wings and control surfaces into multiple separate modules, overcoming the limitations of small equipment molding size. It can complete the base molding of high aspect ratio UAVs without the need for large industrial printing equipment, greatly reducing equipment investment and processing costs, while shortening the molding cycle, and adapting to the needs of rapid design iteration and small batch production.

[0017] This invention pre-sets positioning pin holes and limiting reference surfaces on the docking end faces of each split module, and uses positioning fixtures to achieve precise alignment and clamping and solidification, effectively solving the problems of misalignment and low assembly accuracy in split splicing, ensuring the dimensional accuracy and structural integrity of the whole machine after gluing, and improving the gluing strength and structural rigidity of the splicing parts.

[0018] This invention targets stress concentration areas such as module splicing seams, wing leading edges, wing root transition areas, and landing gear mounting bases. It uses layered application of glass fiber prepreg for directional reinforcement, forming a composite load-bearing structure of "PLA matrix + glass fiber composite reinforcement layer". This significantly improves the structural stiffness, bending strength, and fatigue resistance of the entire aircraft, effectively suppresses wing flutter and deformation cracking during flight, and enhances the flight stability and operational life of the UAV.

[0019] The glass fiber prepreg reinforcement of the present invention adopts a room temperature curing process, which does not require special curing equipment such as autoclaves. The process is simple to operate and has low equipment dependence. While significantly improving the structural strength, it can effectively control the weight gain, thus meeting the requirements of lightweight and high structural strength.

[0020] The invention features a smooth overall process and combines the advantages of rapid prototyping, low cost, high precision, and high rigidity. It can effectively solve the technical pain points of existing 3D printed large aspect ratio drones, such as insufficient rigidity, easy vibration, high molding difficulty, and low assembly accuracy. Attached Figure Description

[0021] Figure 1 This is a flowchart of the manufacturing method described in this invention; Figure 2 This is a schematic diagram of the wing segmentation of the high aspect ratio UAV described in this invention; Figure 3 This is a schematic diagram of the fuselage blocks of the high aspect ratio UAV described in this invention; Figure 4 This is a schematic diagram of the operating surface assembly according to the present invention; In the diagram: 11. Wing section 1; 12. Wing section 2; 13. Wing section 3; 14. Wing section 4; 15. Wing section 5; 16. Control surface mounting slot; 17. Wing rear spars positioning hole; 18. Wing front spars positioning hole; 21. Fuselage front hatch; 22. Fuselage section 1; 23. Fuselage section 2; 24. Fuselage section 3; 25. Fuselage rear hatch; 26. Fuselage section 4; 27. Fuselage section 5; 28. Fuselage section 6; 141. Control surface hinge; 142. Rotating shaft; 143. Control surface. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0023] In the description of this application, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0024] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" 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. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0026] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0027] like Figure 1 As shown in the figure, the specific implementation process of the 3D printing drone manufacturing method based on composite material reinforcement described in this embodiment is as follows: S1. Modular design and tooling positioning benchmark construction: Based on the size limitations of small FDM printers and the structural characteristics of high aspect ratio UAV wings, the UAV fuselage, high aspect ratio wings, and control surfaces are divided into sections, limiting the maximum external dimensions of a single section module to less than 250mm×250mm×200mm, thus adapting to the printing range of conventional desktop small FDM printers.

[0028] Reference Figure 2 The single wing is divided into five sections: wing section 1 (11), wing section 2 (12), wing section 3 (13), wing section 4 (14), and wing section 5 (15). The standard wing surface wall thickness is 0.4-0.6 mm, with increased thickness (0.8-1.2 mm) at wing joints and root areas. Stress concentration points are rounded at sharp corners. Each wing section has a limiting reference surface at the joint end, and positioning holes are pre-drilled at the front and rear spars. The front spar positioning hole (18) has a diameter of 10 mm, and the rear spar positioning hole (17) has a diameter of 6 mm. Control surface mounting slots (16) are located on the trailing edge of the wing.

[0029] Reference Figure 3 The machine body is divided into 6 sections. Each section of the machine body has a positioning pin hole with a diameter of 2-4mm and a limit reference surface on the docking end face to ensure the assembly accuracy of the whole machine.

[0030] After completing the block design and datum design, a split 3D printed model with tooling positioning datum is obtained.

[0031] S2, PLA matrix split 3D printing molding: The fuselage, wings, and control surfaces were individually printed using FDM (Fused Deposition Modeling) technology and PLA material. The printing parameters were: printing temperature 195-210℃, printing speed 200-300mm / s, layer thickness 0.2mm, wall thickness 0.4mm, grid-type infill with a 5% infill density, top layer thickness 0.4mm, and bottom layer thickness 0.4mm. Unidirectional layer-by-layer printing with a tree-like support structure was employed.

[0032] After printing, remove the support structure, and polish and clean the burrs and residual debris on the module surface to ensure that the splicing surface is flat and smooth.

[0033] S3. Surface polishing and cleaning treatment: Clean and polish the splicing and bonding areas and the fiberglass reinforcement areas of each modular unit separately: use 600-800 grit sandpaper to evenly and crosswise polish the bonding areas and the fiberglass reinforcement areas; after polishing, wipe twice with anhydrous ethanol to thoroughly remove surface dust, grease and printing residue, and place in a ventilated place at room temperature to dry for 10-15 minutes.

[0034] S4. Tooling positioning and alignment, and overall machine bonding: All the separate modules are fitted with positioning fixtures, and the positioning pin holes and limiting reference surfaces are matched and limited with the positioning structure of the fixtures. Aerospace structural adhesive is applied to the splicing surfaces of each module, and the fixtures are kept in a clamping state and cured at room temperature to complete the bonding and molding of the whole machine.

[0035] The fuselage adopts a multi-point limiting structure, and each segment is fixed by positioning pin holes on each end face in conjunction with G-type clamps; the wings on both sides adopt an integral limiting structure, and each segment of the wing is sequentially threaded and aligned by two standard length carbon fiber hollow tubes with outer diameters of 10mm and 6mm respectively. After the wing is spliced, it is connected to the fuselage.

[0036] The aerospace structural adhesive used is an epoxy-based high-strength structural adhesive, with the adhesive layer thickness controlled at 0.1-0.2mm. Under the tooling clamping condition, it is initially shaped by curing at room temperature for 2-4 hours, and then completely cured by standing for 12 hours.

[0037] S5. Reinforcement with fiberglass prepreg in critical areas: Epoxy resin-based fiberglass prepreg is applied in layers to the module splicing gaps, wing leading edge, wing root transition area, upper and lower surfaces of the fuselage, and landing gear mounting base area of ​​the whole aircraft. After the application is completed, the entire structure is cured at room temperature.

[0038] The fiberglass prepreg is an epoxy resin-based unidirectional fiberglass prepreg with a single-layer thickness of 0.1-0.2 mm. The application method is as follows: one layer of prepreg is applied at each module joint; an additional layer is applied to the wing leading edge area and wing root transition area on top of the joint application; two layers are applied to the front and rear landing gear mounting base areas. Adjacent layers of prepreg are applied using a 0° / 90° cross-laying method.

[0039] After the entire tiling is completed, place it in a room temperature and ventilated environment to cure for 24-36 hours.

[0040] S6. Post-processing and control surface assembly: After curing, remove the positioning fixtures, and grind and repair the excess glue, excess fiberglass material edges, and mounting holes of the entire machine splicing. Then install the operating rudder.

[0041] Reference Figure 4 The specific installation of the control surface is as follows: using the optical axis as the pivot 142, the control surface 143 is connected to the control surface hinge 141 to form a rotating pair, and the control surface hinge 141 is inserted into the control surface mounting slot 16 of the corresponding wing and fixed with screws.

[0042] After assembly, a 3D-printed high aspect ratio drone reinforced with glass fiber composite material is obtained.

[0043] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for manufacturing a 3D-printed drone based on composite material reinforcement, characterized in that, Includes the following steps: Based on the size limitations of FDM printers and the structural characteristics of high aspect ratio UAVs, the UAV fuselage, high aspect ratio wings, and control surfaces are divided into blocks. Positioning pin holes and limiting reference surfaces are reserved on the docking end faces of each block, and a tooling positioning reference structure is constructed to obtain a block 3D printed model with tooling positioning reference. The FDM (Fused Deposition Modeling) process is used, and PLA material is selected to print each separate module piece by piece. After printing, the support structure is removed, and the burrs and residual debris between layers on the module surface are polished and cleaned. The splicing and bonding areas of each modular unit and the glass fiber reinforcement areas are polished and cleaned. All the separate modules are fitted with positioning fixtures, and the positioning pin holes and limiting reference surfaces are matched and limited with the positioning structure of the fixtures. Aerospace structural adhesive is applied to the splicing surfaces of each module, and the fixtures are kept in a clamping state and cured at room temperature to complete the bonding and molding of the whole machine. Epoxy resin-based fiberglass prepreg is applied in layers to the module splicing gaps, wing leading edge, wing root transition area, upper and lower surfaces of the fuselage, and landing gear mounting base area of ​​the whole aircraft. After the application is completed, the entire structure is cured at room temperature. After curing, the positioning fixtures are removed, the whole machine is polished and repaired, and the operating control surfaces are installed to obtain a 3D-printed high aspect ratio UAV based on glass fiber composite material reinforcement.

2. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The maximum external dimensions of the single-piece modular unit are less than 250mm×250mm×200mm, which is suitable for the printing range of a small desktop FDM printer; the single-sided wing is divided into 5 pieces, and the fuselage is divided into 6 pieces.

3. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 2, characterized in that, The standard wing surface wall thickness is set to 0.4-0.6mm, while the wall thickness at the wing splicing position and wing root area is increased to 0.8-1.2mm, and the stress concentration sharp corners are rounded. Positioning holes with diameters of 10mm and 6mm are respectively set at the front and rear beam positions of each wing segment joint, and positioning pin holes with diameters of 2-4mm are set at each fuselage segment joint.

4. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The specific FDM printing process parameters are as follows: printing temperature 195-210℃, printing speed 200-300mm / s, printing layer thickness 0.2mm, printing wall thickness 0.4mm, using grid-type filling with a filling density of 5%, and the thickness of the top and bottom layers are both 0.4mm; printing adopts a unidirectional layer-by-layer printing method, and the support structure is a tree-like support.

5. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The specific sanding and cleaning process is as follows: use 600-800 grit sandpaper to evenly and crosswise sand the adhesive area and the glass fiber reinforcement area; after sanding, wipe twice with anhydrous ethanol to thoroughly remove surface dust, grease and printing residue, and place in a ventilated place at room temperature to air dry for 10-15 minutes.

6. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The fuselage adopts a multi-point limiting structure, and each segment is fixed by positioning pin holes on each end face in conjunction with special clamps; the wings on both sides adopt an integral limiting structure, and each segment of the wing is sequentially threaded and aligned by two standard length carbon fiber hollow tubes with different outer diameters. After the wing is spliced, it is connected to the fuselage.

7. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The aerospace structural adhesive is an epoxy-based high-strength structural adhesive with a layer thickness controlled at 0.1-0.2 mm. Under tooling clamping conditions, it is initially shaped by curing at room temperature for 2-4 hours, followed by complete curing by static standing for 12 hours.

8. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The glass fiber prepreg is an epoxy resin-based unidirectional glass fiber prepreg with a single layer thickness of 0.1-0.2 mm; adjacent layers of prepreg are laid in a 0° / 90° cross-laying manner.

9. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 8, characterized in that, One layer of prepreg is applied to the seams of each module; an additional layer is applied to the leading edge area of ​​the wing and the transition area of ​​the wing root on top of the seam application; two layers are applied to the front and rear landing gear mounting base areas; after the overall application is completed, the surface is placed in a ventilated environment at room temperature for 24-36 hours to cure.

10. The method for manufacturing a 3D-printed drone based on composite material reinforcement according to claim 1, characterized in that, The specific installation steps of the control surface are as follows: the control surface is connected to the hinge plate using an optical axis to form a rotating pair, and the hinge plate is inserted into the corresponding wing groove and then fixed with screws.

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