3D printing preparation and application method of aircraft assembly part positioning scribe template

Abstract

This invention relates to the interdisciplinary field of aircraft assembly technology and 3D printing, and particularly to a 3D printing preparation and application method for a positioning and scribing template for aircraft assembly parts. The technical solution is as follows: A 3D printing preparation and application method for a positioning and scribing template for aircraft assembly parts includes the following steps: S1, Digital design of the template structure: Based on the positioning reference surface and opening requirements of the aircraft assembly parts, a three-dimensional model of the template is constructed in 3D design software; local thickening and mesh reinforcement are applied to key parts of the positioning reference surface and scribing guide holes in the model, while a lightweight filling structure design is adopted for non-critical areas. This invention effectively overcomes the inherent defects of traditional metal templates, realizes rapid customization and delivery of templates, and significantly shortens the production and design modification cycle.

Description

Technical Field

[0001] This invention relates to the field of interdisciplinary technology of aircraft assembly process and 3D printing, and in particular to a 3D printing preparation and application method of a positioning and marking template for aircraft assembly parts. Background Technology

[0002] Currently, the positioning, scribing, and drilling operations for aircraft assemblies primarily rely on metal templates. The fabrication process for these traditional templates is complex, involving multiple processing steps, resulting in a long overall design and production cycle. Furthermore, once a metal template is formed, it cannot be modified, lacking versatility across different assembly models. Individual templates need to be fabricated and stored, leading to poor flexibility and high overall costs. In addition, the significant weight of metal templates makes them inconvenient to handle, align, and adjust on the assembly site, impacting operational efficiency. Although 3D printing technology is widely used in the manufacturing of general-purpose parts, a systematic solution has yet to be developed for the rapid fabrication and application of specialized templates that meet the high precision, deformation resistance, and stringent assembly processes required for aircraft assembly. Therefore, it cannot directly replace the aforementioned traditional metal templates. Summary of the Invention

[0003] This invention proposes a 3D printing preparation and application method for positioning and marking templates for aircraft assembly parts, which solves the problems of traditional metal aircraft assembly templates being bulky, unmodifiable, and having long production cycles in the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for 3D printing and application of a positioning and marking template for aircraft assembly parts includes the following steps: S1. Digital design of template structure: Based on the positioning reference surface and opening requirements of aircraft assembly parts, a three-dimensional model of the template is constructed in three-dimensional design software; local thickening and mesh reinforcement design are carried out on the key parts of the positioning reference surface and scribing guide hole in the model, and lightweight filling structure design is adopted for non-critical areas. S2, 3D printing material and equipment selection: Engineering plastics with tensile strength ≥80 MPa, heat distortion temperature ≥120℃, and dimensional stability ≤0.2% are selected as printing materials; Fused Deposition Modeling (FDM) 3D printers with printing accuracy ≤±0.1mm are selected; S3, 3D printing parameter optimization: For the critical parts, use a lower layer height, a higher infill rate, and a lower printing speed; for the non-critical areas, use a higher layer height, a lower infill rate, and a higher printing speed; use a soluble support material during printing; S4. Template post-processing and accuracy verification: After removing the support material, the positioning reference surface and the inner wall of the guide hole of the template are polished; the dimensional accuracy of the template is checked using measuring equipment to ensure that it meets the scribing accuracy requirements of aircraft assembly parts. S5. Template Application: The processed 3D printed template is aligned and fixed with the corresponding surface of the aircraft assembly through its positioning reference surface. The template's scribing guide structure is used to perform positioning or scribing operations on the assembly. After a single assembly is completed, the template can be removed and reused or reprinted after modifying the 3D model according to the new model of the assembly.

[0005] Furthermore, in step S1, the local thickening design makes the thickness of the key part reach 3-5mm, and the lightweight filling structure is a honeycomb filling structure; in step S2, the engineering plastic is PA6 material with 30% glass fiber added.

[0006] Furthermore, in step S3, the parameters for printing the critical parts are: a printing layer height of 0.1 mm, a fill rate of 80%, and a printing speed of 30 mm / s; the parameters for printing the non-critical areas are: a printing layer height of 0.2 mm, a fill rate of 40%, and a printing speed of 50 mm / s; and the soluble support material is polyvinyl alcohol (PVA).

[0007] Furthermore, in step S4, the polishing process is to use 2000-grit sandpaper to polish the surface roughness Ra of the positioning reference surface and the inner wall of the guide hole to be ≤1.6μm; the accuracy verification is to use a coordinate measuring machine to detect the positioning hole coordinates and the flatness of the reference surface of the template, and control the error within ±0.2mm.

[0008] Furthermore, in step S5, the scribing guide structure is a scribing guide groove formed on the template, and scribing is performed along the guide groove by a scribing needle during application; and the 3D printed template prepared by the method is suitable for positioning and scribing operations of pipes, flanges or brackets on aircraft.

[0009] Furthermore, in step S1, the mesh reinforcement design refers to constructing a reinforcing rib or mesh-like internal support structure in the thickened area of ​​the critical part.

[0010] Furthermore, in step S2, the selected fused deposition modeling (FDM) 3D printer must have a printing accuracy of ≤±0.1mm, and its adjustable printing parameters must support the requirements of differentiated printing layer height, infill rate, and printing speed for critical and non-critical areas as described in step S3.

[0011] Furthermore, in step S3, during 3D printing, the plane where the positioning reference surface of the template is located is parallel to the construction plane of the printing platform, and the critical parts are printed before the non-critical areas.

[0012] Furthermore, in step S4, the accuracy verification also includes using standard gauge blocks or plug gauges to inspect the width of the scribing guide groove to ensure its matching accuracy with the scribing needle.

[0013] Furthermore, in step S5, the alignment and fixing are achieved by engaging the positioning groove on the template with the vertical rib on the aircraft assembly, and using an arc clamp to clamp the positioning end face of the template with the part.

[0014] The positive effects of this invention are as follows: The 3D printing preparation and application method provided by this invention can effectively overcome the inherent defects of traditional metal templates. This method enables rapid template customization and delivery, significantly shortening the production and design modification cycle. In terms of cost, thanks to changes in materials and processes, the preparation cost of templates is greatly reduced. At the same time, the prepared templates are very lightweight, greatly improving the convenience and efficiency of assembly site operations. Furthermore, this method has excellent flexibility; through digital models, it can easily adapt to different models of assemblies, enabling rapid response for small-batch, multi-variety production and avoiding large amounts of physical inventory. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a three-dimensional model of a 3D-printed positioning template in an embodiment of the present invention; Figure 2 This is a schematic diagram of the positioning template in an embodiment of the present invention; Figure 3 This is a schematic diagram of the positioning groove engaging the vertical rib of the part in an embodiment of the present invention; Figure 4 This is a schematic diagram of the part positioning surface inside the tube in an embodiment of the present invention; Figure 5 This is a schematic diagram of placing a part into the part positioning surface in an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0017] A 3D printing preparation and application method for a positioning and scribing template for aircraft assembly parts includes the following steps: S1, Digital design of the template structure: Based on the positioning reference surface and opening requirements of the aircraft assembly parts, a 3D model of the template is constructed in 3D design software; local thickening and mesh reinforcement are carried out on the positioning reference surface and key parts of the scribing guide hole in the model, and a lightweight filling structure design is adopted for non-critical areas; S2, Selection of 3D printing materials and equipment: Engineering plastics with tensile strength ≥80MPa, heat distortion temperature ≥120℃, and dimensional stability ≤0.2% are selected as printing materials; Fused Deposition Modeling (FDM) with a printing accuracy ≤±0.1mm is selected. 3D printer; S3, 3D printing parameter optimization: For critical parts, use a lower layer height, higher infill rate, and lower printing speed; for non-critical areas, use a higher layer height, lower infill rate, and higher printing speed; use a soluble support material during printing; S4, Template post-processing and accuracy verification: After removing the support material, grind the positioning reference surface and the inner wall of the guide hole of the template; use measuring equipment to check the dimensional accuracy of the template to ensure it meets the scribing accuracy requirements of aircraft assembly parts; S5, Template application: Align and fix the processed 3D printed template with the corresponding surface of the aircraft assembly parts using its positioning reference surface; use the scribing guide structure of the template to perform positioning or scribing operations on the assembly parts; after a single assembly is completed, remove the template for reuse or reprint it after modifying the 3D model according to the new model assembly parts.

[0018] In step S1, the local thickening design increases the thickness of the critical parts to 3-5 mm, and the lightweight filling structure is a honeycomb filling structure. In step S2, the engineering plastic is PA6 material with 30% glass fiber added. In step S3, the printing parameters for the critical parts are: printing layer height 0.1 mm, fill rate 80%, and printing speed 30 mm / s; the printing parameters for the non-critical areas are: printing layer height 0.2 mm, fill rate 40%, and printing speed 50 mm / s; and the soluble support material is polyvinyl alcohol (PVA). In step S4, the polishing process uses 2000-grit sandpaper to polish the surface roughness Ra of the positioning reference surface and the inner wall of the guide hole to ≤1.6 μm; the accuracy verification uses a coordinate measuring machine to check the positioning hole coordinates and reference surface flatness of the template, and controls the error within ±0.2 mm. In step S5, the scribing guide structure is a scribing guide groove opened on the template. During application, scribing is performed along the guide groove using a scribing needle. Furthermore, the 3D printed template prepared by the method is suitable for positioning and scribing operations of pipes, flanges, or brackets on aircraft.

[0019] In addition, in step S1, the mesh reinforcement design refers to constructing reinforcing ribs or a mesh-like internal support structure within the thickened area of ​​the critical parts. In step S2, the selected fused deposition modeling (FDM) 3D printer must have a printing accuracy of ≤±0.1mm, and its adjustable printing parameters must support the requirements of differentiated printing layer height, infill rate, and printing speed for critical and non-critical areas as described in step S3. In step S3, during 3D printing, the plane of the template's positioning reference surface is parallel to the printing platform's construction plane, and the critical parts are printed before non-critical areas. In step S4, the accuracy verification also includes using standard gauge blocks or plug gauges to check the width of the scribing guide groove to ensure its matching accuracy with the scribing needle. In step S5, the alignment and fixing are achieved by engaging the positioning groove on the template with the vertical rib on the aircraft assembly, and using an arc clamp to clamp the positioning end face of the template to the part. Example 2

[0020] The following detailed description, using a specific embodiment, illustrates the 3D printing preparation and application method of the aircraft assembly positioning and marking template described in Example 1. This embodiment takes the preparation and application of a "positioning and marking template for assembling the inner baffle of a certain type of aircraft tee pipe" as an example.

[0021] Step 1: Digital Design of Template Structure First, clarify the assembly requirements. For the inner baffle of this tee pipe, the assembly positioning reference is the flange end face at the middle end of the pipe, and the positions of several connection holes need to be marked on the baffle.

[0022] 3D modeling: In 3D design software (such as CATIA, UG NX, etc.), a 3D solid model of the positioning template is constructed based on the end face shape of the flange and the coordinate position of the hole to be opened.

[0023] Structural optimization design: Key parts are reinforced. The positioning reference surface that contacts the flange and the scribing guide groove used to guide the scribing needle are locally thickened. The thickness is set to 5mm, and grid-like reinforcing ribs are distributed inside the thickened area to ensure structural strength and rigidity while reducing weight.

[0024] Lightweighting of non-critical areas: For the large, non-load-bearing, non-positioning areas in the middle of the template, a honeycomb-shaped perforated structure is designed with a wall thickness of 2mm to minimize the overall weight of the template.

[0025] Step 2: Selection of 3D Printing Materials and Equipment Material Selection: PA6 (Nylon 6) engineering plastic granules with 30% chopped glass fiber were selected as the printing material. The measured tensile strength of this material is greater than 80MPa, the heat distortion temperature is higher than 120℃ (able to withstand summer factory environments), the molding shrinkage rate is small, and the dimensional stability is high (<0.2%), which can meet the mechanical and environmental requirements of aircraft assembly sites.

[0026] Equipment Selection: Select an industrial-grade fused deposition modeling (FDM) 3D printer with a printing accuracy (dimensional tolerance) ≤ ±0.1mm. The printer must have dual nozzle functionality (to allow the use of soluble support materials), and its software and hardware must support setting differentiated printing parameters for different areas of the model within a single printing job.

[0027] Step 3: 3D Printing Parameter Optimization and Printing Execution In the slicing software, the printing parameters of the above 3D model are set, and a differentiated printing strategy is implemented: Key area parameters: Set higher print quality for the areas containing the "positioning reference plane" and the "scrubbing guide groove". Print layer height: 0.1mm Fill rate: 80% (solid fill) Printing speed: 30 mm / s Non-critical area parameters: For lightweight areas with honeycomb filling, set parameters that prioritize efficiency: Print layer height: 0.2mm Fill rate: 40% Printing speed: 50 mm / s Support and Printing: To ensure the printing quality of the scribe guide groove with its suspended structure, water-soluble polyvinyl alcohol (PVA) was selected as the support material. The model was placed with its positioning reference surface facing the printing platform and sliced ​​before printing began. The printer operated according to the settings, printing at high precision and slow speed in critical areas and at a higher speed in non-critical areas. The overall printing time was approximately 15 hours.

[0028] Step 4: Sample post-processing and accuracy verification Post-processing: After printing, place the printed base plate with the template in warm water and soak for about 4-6 hours to completely dissolve and detach the PVA support material. Remove the template and gently hand-polish the positioning reference surface and the inner wall of the scribing guide groove with 2000-grit sandpaper until the surface roughness Ra reaches about 1.6μm, ensuring that the positioning surface is free of burrs and the scribe groove is smooth.

[0029] Accuracy verification: The template was inspected using a coordinate measuring machine (CMM). The template was fixed on the measuring platform, and the flatness of its positioning reference surface was measured, with a value of 0.05 mm.

[0030] Measure the center coordinates of each scribing guide groove and its relative position to the reference surface. The maximum positional error is ±0.08mm.

[0031] Use a standard plug gauge to check the width of the scribing guide groove and confirm that the clearance with the standard scribing needle meets the requirements.

[0032] All test results met the requirements for scribing accuracy (±0.2mm) of aircraft assembly parts.

[0033] Step 5: Sample Application At the aircraft assembly site, operators use this 3D-printed template to assemble the inner baffle of the T-junction pipe: Alignment and Fixing: Precisely insert the positioning groove designed on the template into the vertical rib on the inside of the pipeline, while ensuring that the positioning end face of the template is flush with the flange end face of the pipeline. Then, use a lightweight bow-shaped clamp to clamp and fix the template to the pipeline. The entire fixing process is completed within 30 seconds.

[0034] Scribing operation: Place the tip of the scriber into the scriber guide groove of the template and scribing a clear opening position line on the baffle part along the groove wall.

[0035] Repeating and Iteration: After the inner baffle of this batch is assembled, the template is removed, inspected for damage, and can then be used for the assembly of the next part of the same model. If a new model of piping is to be assembled later, the designer only needs to modify the dimensions based on the original 3D model, and then send it to the 3D printer to quickly produce a new template, without having to wait for the long processing cycle of traditional metal templates. Example 3

[0036] like Figure 1-5 As shown in Example 2, the following describes the implementation process of the present invention in more detail, taking "positioning template for assembling the inner baffle of a three-way pipe at a certain location on a certain type of aircraft" as an example.

[0037] Structural design: Based on the flange of the middle end face of the tee pipe, design a three-dimensional model of the positioning template: the positioning reference surface is 250mm×80mm in size and 5mm thick; non-critical areas are filled with 2mm honeycomb holes.

[0038] Materials and Equipment: PA6+30% glass fiber material was selected, and Creality K1 MAX FDM printer was used.

[0039] Printing parameters: Positioning surface area -- layer height 0.1mm, fill rate 80%, speed 30mm / s; other areas layer height 0.2mm, fill rate 40%, speed 50mm / s.

[0040] Post-processing: Remove the support, sand the positioning surface with 2000-grit sandpaper, and coordinate measuring machine (CMM) inspection shows that the center distance error of the positioning hole is ±0.08mm and the flatness of the reference surface is 0.05mm, which meets the requirements.

[0041] Application effect: During on-site assembly, the template can be fixed within 30 seconds through the positioning groove and positioning end face. After positioning the parts, the detection error is ±0.1mm (meeting the aircraft assembly accuracy standard). Compared with the traditional metal template (preparation cycle of 10 days and weight of 20kg), the template preparation cycle of this embodiment is 2 days and the weight is 1kg, which significantly improves efficiency.

[0042] in, Figure 1 This is a 3D model of a 3D printed positioning template, where 1 is the positioning groove, 2 is the positioning end face, and 3 is the part mounting surface. Figure 2 As a positioning template; Figure 3 Diagram showing the positioning groove for inserting the vertical rib of the part, with the end face tightly against the part, and the bow-shaped clamp in a clamping state. Figure 4 For the positioning surface of the parts inside the tube, Figure 5 Place the part on the positioning surface and define its position relative to the pipe wall.

[0043] The above-described embodiments are detailed and specific, illustrating preferred embodiments of the present invention. They are only used to illustrate the technical ideas and features of the present invention, with the aim of enabling those skilled in the art to understand the content of the present invention and implement it accordingly. However, they are not limited to the present invention, and the patent scope of the present invention cannot be limited by this embodiment alone. That is, any equivalent changes or modifications made to the spirit disclosed in the present invention, without departing from the structure of the present invention, such as local improvements within the system and modifications or transformations between subsystems, are still within the patent scope of the present invention.

Claims

1. A method for the 3D printing preparation and application of a positioning and marking template for aircraft assembly parts, characterized in that, Includes the following steps: S1. Digital design of template structure: Based on the positioning reference surface and opening requirements of aircraft assembly parts, a three-dimensional model of the template is constructed in three-dimensional design software; local thickening and mesh reinforcement design are carried out on the key parts of the positioning reference surface and scribing guide hole in the model, and lightweight filling structure design is adopted for non-critical areas. S2, 3D printing material and equipment selection: Engineering plastics with tensile strength ≥80 MPa, heat distortion temperature ≥120℃, and dimensional stability ≤0.2% are selected as printing materials; Fused Deposition Modeling (FDM) 3D printers with printing accuracy ≤±0.1mm are selected; S3, 3D printing parameter optimization: For the critical parts, use a lower layer height, a higher infill rate, and a lower printing speed; for the non-critical areas, use a higher layer height, a lower infill rate, and a higher printing speed; use a soluble support material during printing; S4. Template post-processing and accuracy verification: After removing the support material, the positioning reference surface and the inner wall of the guide hole of the template are polished; the dimensional accuracy of the template is checked using measuring equipment to ensure that it meets the scribing accuracy requirements of aircraft assembly parts. S5. Template Application: The processed 3D printed template is aligned and fixed with the corresponding surface of the aircraft assembly through its positioning reference surface. The template's scribing guide structure is used to perform positioning or scribing operations on the assembly. After a single assembly is completed, the template can be removed and reused or reprinted after modifying the 3D model according to the new model of the assembly.

2. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S1, the local thickening design makes the thickness of the key part reach 3-5mm, and the lightweight filling structure is a honeycomb filling structure; in step S2, the engineering plastic is PA6 material with 30% glass fiber added.

3. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 2, characterized in that, In step S3, the parameters for printing the critical parts are: a printing layer height of 0.1 mm, a fill rate of 80%, and a printing speed of 30 mm / s; the parameters for printing the non-critical areas are: a printing layer height of 0.2 mm, a fill rate of 40%, and a printing speed of 50 mm / s; and the soluble support material is polyvinyl alcohol (PVA).

4. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 3, characterized in that, In step S4, the polishing process is to use 2000-grit sandpaper to polish the surface roughness Ra of the positioning reference surface and the inner wall of the guide hole to be ≤1.6μm; the accuracy verification is to use a coordinate measuring machine to detect the positioning hole coordinates and the flatness of the reference surface of the template, and control the error within ±0.2mm.

5. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S5, the scribing guide structure is a scribing guide groove opened on the template. During application, scribing is performed along the guide groove using a scribing needle. Furthermore, the 3D printed template prepared by the method is suitable for positioning and scribing operations of pipes, flanges, or brackets on aircraft.

6. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S1, the mesh reinforcement design refers to constructing a reinforcing rib or mesh-like internal support structure in the thickened area of ​​the critical part.

7. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S2, the selected fused deposition modeling (FDM) 3D printer must have a printing accuracy of ≤±0.1mm, and its adjustable printing parameters must support the requirements of differentiated printing layer height, infill rate, and printing speed for critical and non-critical areas as described in step S3.

8. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1 or 3, characterized in that, In step S3, during 3D printing, the plane where the positioning reference surface of the template is located is parallel to the construction plane of the printing platform, and the critical parts are printed before the non-critical areas.

9. The method for 3D printing preparation and application of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S4, the accuracy verification also includes using standard gauge blocks or plug gauges to inspect the width of the scribing guide groove to ensure its matching accuracy with the scribing needle.

10. The 3D printing preparation and application method of a positioning and marking template for aircraft assembly parts according to claim 1, characterized in that, In step S5, the alignment and fixing are achieved by engaging the positioning groove on the template with the vertical rib on the aircraft assembly, and using an arc clamp to clamp the positioning end face of the template with the part.

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