Aircraft sealant application and thickness control method and tool

Abstract

The application provides an aircraft sealant coating thickness control tool, comprising a connecting base, an inner thread / quick plug buckle structure is arranged in the connecting base, a market mainstream manual glue gun and an automatic coating machine nozzle are matched, a glue outlet is in sealing connection with the connecting base, an adjustable thickness adjusting scraper is a core thickness control component, is located behind the glue outlet, the vertical distance between the bottom surface of the scraper and the surface of a workpiece is the preset glue layer thickness, a scale adjusting mechanism is arranged above the scraper, has a millimeter level scale, a rotating adjusting knob can be used for fine tuning the height of the scraper, the target glue layer thickness is accurately set, after adjustment, the height is fixed through a locking screw to prevent displacement during operation, a guide wheel is installed at the bottom of a limiting stop edge and is in rolling contact with the surface of the workpiece, walking resistance is reduced, uniform speed of coating is ensured, and the guide wheel is especially suitable for curved surface and long distance joint coating; meanwhile, the application also provides an aircraft sealant coating thickness control method; and the application solves the defects of difficult accurate control of the coating thickness of the existing aircraft sealant, poor tool universality, low operation efficiency and unstable sealing quality.

Description

Technical Field

[0001] This application belongs to the technical field of sealant coating process for structural parts such as fuselage and wings during the assembly of aircraft structural components, and particularly relates to a method and tool for controlling the thickness of sealant coating on aircraft. Background Technology

[0002] Aircraft structural sealing is a core process ensuring the airtightness, oil tightness, waterproofness, and flight safety of the entire aircraft. The thickness of the sealant layer is a key indicator determining the seal life, bonding strength, and anti-aging performance. The aviation industry has stringent standards for sealant layer thickness. The sealant layer thickness for conventional joints is required to be controlled between 0.2 and 1.0 mm, while the thickness tolerance for fuel tank seals and fastener wrappings must be ≤ ±0.1 mm. Exceeding the thickness standard can easily lead to material waste, surface bulges, deterioration of aerodynamic shape, and cracking after curing. Insufficient thickness will result in gap leakage, seal failure, and major safety hazards such as fuel tank leakage and cabin air leakage.

[0003] Currently, aircraft assembly sites mainly use manual glue application combined with ordinary glue guns, with some workstations using simple automatic glue application equipment. However, the existing technology has its shortcomings. Summary of the Invention

[0004] Purpose of the invention: Existing automated adhesive application equipment is expensive and complex to debug, and is only suitable for large, regular flat surfaces. It cannot cover irregular curved surfaces, deep and narrow gaps, complex corners, and other working conditions of aircraft, thus limiting its versatility. Therefore, developing a simple, adaptable, high-precision, and easy-to-operate method and supporting tools for controlling the thickness of aircraft sealant application has become an urgent technical problem to be solved in the aerospace assembly field. In a first aspect, this application provides a tool for controlling the thickness of an aircraft sealant application, the tool comprising: Connection base: Features internal thread / quick-fit buckle structure, compatible with mainstream manual glue guns and automatic glue applicator nozzles on the market; Dispensing nozzle: The connecting base is sealed to the dispensing nozzle; Adjustable thickness scraper: The core thickness control component, located behind the glue nozzle. The vertical distance between the bottom surface of the scraper and the surface of the workpiece is the preset glue layer thickness. Scale adjustment mechanism: Located above the scraper, it has millimeter-level scale. Rotating the adjustment knob can finely adjust the height of the scraper up and down to accurately set the target adhesive layer thickness. After adjustment, it is fixed by locking screws to prevent displacement during operation. Guide wheels: Installed at the bottom of the limit stop, they roll in contact with the workpiece surface, reducing travel resistance and ensuring uniform speed of adhesive application. They are especially suitable for applying adhesive to curved surfaces and long-distance joints.

[0005] Preferably, the dispensing nozzle is available in two specifications: a flat nozzle and a round nozzle. The flat nozzle is suitable for applying adhesive over a large area of ​​flat joints, while the round nozzle is suitable for fasteners and point sealing.

[0006] Preferably, the width of the adhesive outlet is designed according to aircraft seam standards to limit the maximum width of the adhesive layer.

[0007] Preferably, the tool further includes: Double-sided limiting guards: Symmetrically set on both sides of the dispensing nozzle, they fit against the workpiece surface, limit the adhesive travel trajectory, prevent the adhesive layer from shifting laterally, and prevent excess adhesive from flowing to both sides.

[0008] Preferably, the scraper is made of an elastic and wear-resistant material to avoid scratching the aircraft skin and coating.

[0009] Preferably, the guide wheel is a small miniature roller.

[0010] Secondly, this application also provides a method for controlling the thickness of an aircraft sealant coating, the method comprising: Applying adhesive to straight joints: Hold the glue gun and make the guide wheel and limit stop close to the surface of the workpiece. Keep the glue gun in a stable position and move it in a straight line at a constant speed. The glue nozzle will continuously dispense glue, and the thickness scraper at the rear will scrape off the excess glue that exceeds the set thickness in real time. The thickness control is completed in one step. Applying adhesive to curved surfaces / corners: Reduce travel speed and rely on guide wheels to naturally turn with the curved surface of the workpiece, without stopping at corners to avoid adhesive buildup; For overhead / side coating: reduce dispensing pressure, slow down the walking speed, use the limiting edge to block the glue flow, and use the scraper to continuously limit and control the thickness to prevent glue flow from causing the thickness to exceed the standard. Applying sealant to narrow grooves and deep slots: A narrow, flat nozzle is used. The entire tool is inserted into the groove and positioned by the double-sided guards to apply a measured amount of sealant to the groove.

[0011] Preferably, the method further includes: After applying adhesive to a single area, there is no need for a second large-area scraping; only minor local defects need to be repaired. The thickness, continuity, and surface flatness of the adhesive layer are inspected using a combination of thickness gauge and visual sampling. Unqualified areas are locally repaired and recoated.

[0012] The beneficial technical effects of this application are as follows: (1) Significantly improved thickness control accuracy: Through mechanical limit and precise scale adjustment, the thickness tolerance of the adhesive layer is stably controlled within ±0.1mm, which fully meets the aviation sealing industry standards, completely solves the problems of uneven thickness, dripping, accumulation and lack of adhesive when manually applying adhesive, reduces oil tank leakage, cabin air leakage and sealant cracking from the source, and improves the overall sealing reliability and service life of the aircraft.

[0013] (2) Strong versatility in working conditions: The modular tool can replace the glue nozzle and quickly adjust the thickness. It is suitable for fully sealed working conditions such as aircraft skin seams, lap joints, deep and narrow grooves, irregular curved surfaces, fasteners, overhead / side coating, etc. It is compatible with manual glue guns and automated glue application equipment and is applicable to all military and civilian aircraft models.

[0014] (3) Protect the surface of the workpiece: The design of elastic scraper + rolling guide wheel has no rigid friction and will not scratch the aircraft skin, protective coating and composite material components, ensuring the aerodynamic shape and surface quality of the aircraft. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the tool provided in the embodiments of this application; Figure 2 This is a schematic diagram of the dispensing nozzle provided in an embodiment of this application; Figure 3 This is a schematic diagram of the scale adjustment mechanism provided in the embodiments of this application; Explanation of reference numerals in the attached drawings: 1-Connecting base, 2-Dispensing nozzle, 3-Double-sided limiting edge, 4-Adjustable thickness scraper, 5-Guide wheel, 6-Locking assembly, 7-Scale adjustment mechanism. Detailed Implementation

[0017] The following describes the embodiments and appendices. Figure 1 -Appendix Figure 3 The present invention will be described in further detail, but the embodiments of the present invention are not limited thereto.

[0018] This invention addresses the shortcomings of existing aircraft sealant coatings, such as difficulty in accurately controlling coating thickness, poor tool versatility, low operational efficiency, and unstable sealing quality, by providing a method and tool for controlling the coating thickness of aircraft sealants.

[0019] It enables quantitative, real-time, and limit control of the sealant layer thickness, meeting aviation sealing tolerance requirements and significantly reducing the risk of sealing failures such as leakage and cracking. Designed as an integrated, small, dedicated thickness control tool, it is suitable for all working conditions, including straight seams, curved surfaces, narrow seams, corners, overhead coating, and side coating on aircraft. It can be used with conventional manual glue guns and automatic glue application equipment. Simplify the post-application scraping process, reduce rework, lower labor intensity, and improve the efficiency of the application process and product consistency; With its simple structure, low cost, and convenient assembly and disassembly, the thickness control components can be quickly replaced to adapt to different thickness specifications of adhesive application. It is suitable for mass production and on-site maintenance of various military and civilian models.

[0020] This invention consists of two main parts: a dedicated thickness control tool and a matching adhesive coating thickness control process. The tool and process work together to achieve high-precision thickness control of the sealant layer from both hardware limits and process specifications.

[0021] Aircraft sealant application thickness control tool (1) Overall structure of the tool like Figure 1 As shown, this thickness control tool has a modular structure and can be detachably installed at the front of the glue gun nozzle. It mainly consists of seven modules: 1. Connecting base; 2. Glue nozzle; 3. Double-sided limiting guards; 4. Adjustable thickness scraper; 5. Guide wheel; 6. Locking assembly; and 7. Scale adjustment mechanism. The entire tool is made of aerospace-grade aluminum alloy and wear-resistant engineering plastics, featuring a lightweight design with a total weight of ≤80g, allowing it to fit into narrow spaces such as narrow gaps and deep grooves in aircraft.

[0022] (2) Functions and structural details of each component Serial number 1 connecting base: It has an internal thread / quick buckle structure, which is compatible with the mainstream manual glue guns and automatic glue applicator nozzles on the market, so as to achieve quick disassembly and assembly; the base and the glue nozzle are sealed to prevent glue leakage and overflow.

[0023] No. 2 Glue Dispenser: Available in two sizes, flat and round. The flat nozzle is suitable for applying glue to large areas of flat joints, while the round nozzle is suitable for fasteners and spot sealing. The width of the glue outlet is designed according to aircraft joint standards to limit the maximum width of the glue layer.

[0024] Serial number 3 Double-sided limiting guard: Symmetrically set on both sides of the dispensing nozzle, it fits against the surface of the workpiece, limits the dispensing trajectory, prevents the adhesive layer from shifting laterally, and at the same time blocks excess adhesive from flowing to both sides.

[0025] Serial number 4 Adjustable thickness scraper: The core thickness control component, located behind the glue nozzle. The vertical distance between the bottom surface of the scraper and the surface of the workpiece is the preset glue layer thickness. The scraper is made of elastic and wear-resistant material to avoid scratching the aircraft skin and coating.

[0026] Serial number 5: Scale adjustment mechanism: Located above the scraper, it has millimeter-level scale (0.1mm~2.0mm). Rotating the adjustment knob allows for fine adjustment of the scraper height, accurately setting the target adhesive layer thickness. After adjustment, it is fixed by locking screws to prevent displacement during operation.

[0027] No. 6 guide wheel: a small and miniature roller installed at the bottom of the limit stop, which rolls in contact with the workpiece surface, reducing travel resistance and ensuring uniform speed of adhesive application. It is especially suitable for applying adhesive to curved surfaces and long-distance joints.

[0028] (3) Tool adjustment mode Coarse adjustment: According to the drawing requirements, adjust the thickness scraper to the target thickness range by referring to the scale; Fine-tuning: Make minor adjustments based on sealant viscosity and ambient temperature to lock and tighten the components; Operating condition switching: Change the flat / round nozzle to adapt to different sealing parts such as joints, fasteners, and deep seams.

[0029] Aircraft sealant coating thickness control method This method relies on the aforementioned thickness control tools and consists of five main steps: preliminary preparation, parameter setting, test adhesive verification, formal adhesive application, and final inspection. It is applicable to room temperature curing aerospace sealants, thixotropic sealants, and fuel tank sealants. The specific process is as follows: Step 1: Pre-construction preparation (1) Workpiece preparation: Clean the oil, dust, old glue and oxide layer on the surface of the aircraft skin, seams and fasteners to ensure that the bonding surface is clean and dry and meets the aviation sealing construction standards; (2) Tool assembly: Select the corresponding specification of the dispensing nozzle according to the type of sealing part, fix the thickness control tool to the front end of the glue gun, and check the connection sealing. (3) Environmental confirmation: Record the on-site temperature and humidity, and preheat the high-viscosity sealant appropriately to ensure stable flowability of the sealant.

[0030] Step 2: Preset thickness parameters (1) Set the height of the fixed thickness scraper according to the drawings and sealing technical requirements through the scale adjustment mechanism; (2) After adjustment, tighten the locking screws to lock the scraper position.

[0031] Step 3: Test Glue Thickness Verification Test coating is performed on a waste board of the same material. After the adhesive is applied, the thickness of the adhesive layer is checked at multiple points using a digital thickness gauge. If the deviation exceeds the tolerance (>±0.1mm), the height of the scraper is readjusted until the thickness of the adhesive meets the standard before formal construction can begin.

[0032] Step 4: Apply adhesive in sections at a uniform speed (1) Applying glue to straight joints: Hold the glue gun and make the guide wheel and limit stop close to the surface of the workpiece. Keep the glue gun in a stable position and move it in a straight line at a uniform speed. The glue nozzle continuously dispenses glue, and the thickness scraper at the rear scrapes off the excess glue that exceeds the set thickness in real time. The thickness control is completed in one step. (2) Applying adhesive to curved surfaces / corners: Reduce the travel speed and rely on the guide wheels to turn naturally with the curved surface of the workpiece, without stopping at corners, to avoid adhesive buildup; (3) Overhead / side coating conditions: Reduce the dispensing pressure, slow down the walking speed, use the limiting edge to block the flow of adhesive, and continuously limit the thickness with the scraper to prevent the adhesive from flowing and causing the thickness to exceed the standard. (4) Applying adhesive to narrow grooves and deep slots: Use a narrow, flat nozzle to apply the adhesive. Insert the entire tool into the groove and position it using the double-sided baffles to apply the adhesive in a measured amount.

[0033] Step 5: Finishing and Quality Inspection After the adhesive is applied to a single area, there is no need for a second large-area scraping. Only minor defects in the local area need to be repaired. The thickness, continuity and surface flatness of the adhesive layer are checked by a combination of thickness gauge and visual sampling. Unqualified areas are locally re-coated with adhesive.

[0034] In other embodiments of this application, an aircraft sealant coating thickness control tool is provided, comprising: 1. a connecting base; 2. a dispensing nozzle; 3. double-sided limiting edges; 4. an adjustable thickness scraper; 5. a guide wheel; 6. a locking assembly; and 7. a scale adjustment mechanism. The connecting base is detachably fixed to the dispensing end of a glue gun, with its lower end sealingly connected to the dispensing nozzle. The limiting edges are symmetrically arranged on the left and right sides of the dispensing nozzle, with guide wheels installed at their bottoms. The adjustable thickness scraper is located behind the dispensing nozzle, and a scale adjustment mechanism is connected above it, with a locking assembly attached to the scale adjustment mechanism. The vertical distance between the bottom surface of the thickness scraper and the workpiece surface is the preset coating thickness of the sealant, and the scraper height is continuously adjustable via the scale adjustment mechanism.

[0035] like Figure 2 The dispensing nozzle shown in Figure 2 has two replaceable structures: a flat nozzle and a round nozzle. The flat nozzle is used for applying adhesive to flat joints, while the round nozzle is used for dot sealing of aircraft fasteners. The width of the dispensing nozzle is matched with the standard sealing joint of the aircraft.

[0036] like Figure 3 As shown, the scale adjustment mechanism number 7 is set with a scale of 0.1mm to 2.0mm, and the thickness adjustment accuracy is 0.05mm; the thickness scraper is made of elastic wear-resistant engineering plastic material, and the guide wheel is a miniature silent roller.

[0037] In other embodiments of this application, a method for controlling the thickness of aircraft sealant application based on the aforementioned tool is provided, comprising the following steps: Workpiece pretreatment: Clean impurities from the surface of the aircraft sealing parts to ensure that the bonding surfaces are clean and dry; Tool assembly and parameter setting: Select the corresponding nozzle according to the sealing part, install the thickness control tool at the front end of the glue gun, set the thickness scraper height according to the sealing standard through the scale adjustment mechanism, and lock it in place; Test coating verification: Apply the adhesive to a test board of the same material, check the thickness of the adhesive layer, and fine-tune the scraper until the thickness meets the tolerance requirements; Formal glue application: Make the guide wheel and limit stop edge fit against the workpiece surface, keep the glue gun in a stable and uniform position and move at a constant speed. While the glue nozzle is dispensing glue, the thickness scraper scrapes off the excess glue in real time to complete the glue layer limit and thickness control. Adjust the walking speed and glue dispensing pressure for different working conditions such as straight lines, curved surfaces, corners, overhead coating, and narrow gaps. Inspection and repair: After the adhesive is applied, randomly check the thickness and appearance of the adhesive layer, and repair any defects locally.

[0038] In the confined space after the assembly of a certain type of aircraft control surface structural component, rapid application of sealant was achieved, and the sealant thickness, size, and surface quality all met the usage requirements.

[0039] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A tool for controlling the thickness of aircraft sealant application, characterized in that, The tools include: Connection base: Features internal thread / quick-fit buckle structure, compatible with mainstream manual glue guns and automatic glue applicator nozzles on the market; Dispensing nozzle: The connecting base is sealed to the dispensing nozzle; Adjustable thickness scraper: The core thickness control component, located behind the glue nozzle. The vertical distance between the bottom surface of the scraper and the surface of the workpiece is the preset glue layer thickness. Scale adjustment mechanism: Located above the scraper, it has millimeter-level scale. Rotating the adjustment knob can finely adjust the height of the scraper up and down to accurately set the target adhesive layer thickness. After adjustment, it is fixed by locking screws to prevent displacement during operation. Guide wheels: Installed at the bottom of the limit stop, they roll in contact with the workpiece surface, reducing travel resistance and ensuring uniform speed of adhesive application. They are especially suitable for applying adhesive to curved surfaces and long-distance joints.

2. The tool according to claim 1, characterized in that, The dispensing nozzle comes in two specifications: a flat nozzle and a round nozzle. The flat nozzle is suitable for applying adhesive to large areas of flat joints, while the round nozzle is suitable for fasteners and spot sealing.

3. The tool according to claim 2, characterized in that, The width of the adhesive outlet is designed according to aircraft seam standards to limit the maximum width of the adhesive layer.

4. The tool according to claim 1, characterized in that, The tool also includes: Double-sided limiting guards: Symmetrically set on both sides of the dispensing nozzle, they fit against the workpiece surface, limit the adhesive travel trajectory, prevent the adhesive layer from shifting laterally, and prevent excess adhesive from flowing to both sides.

5. The tool according to claim 1, characterized in that, The scraper is made of a flexible and wear-resistant material to prevent scratches on the aircraft skin and coating.

6. The tool according to claim 1, characterized in that, The guide wheel is a small, miniature roller.

7. A method for controlling the thickness of an aircraft sealant coating, characterized in that, The method includes: Applying adhesive to straight joints: Hold the glue gun and make the guide wheel and limit stop close to the surface of the workpiece. Keep the glue gun in a stable position and move it in a straight line at a constant speed. The glue nozzle will continuously dispense glue, and the thickness scraper at the rear will scrape off the excess glue that exceeds the set thickness in real time. The thickness control is completed in one step. Applying adhesive to curved surfaces / corners: Reduce travel speed and rely on guide wheels to naturally turn with the curved surface of the workpiece, without stopping at corners to avoid adhesive buildup; For overhead / side coating: reduce dispensing pressure, slow down the walking speed, use the limiting edge to block the glue flow, and use the scraper to continuously limit and control the thickness to prevent glue flow from causing the thickness to exceed the standard. Applying sealant to narrow grooves and deep channels: A narrow, flat nozzle is used. The entire tool is inserted into the groove and positioned by the double-sided baffles to apply a measured amount of sealant to the groove.

8. The method according to claim 7, characterized in that, The method further includes: After applying adhesive to a single area, there is no need for a second large-area scraping; only minor local defects need to be repaired. The thickness, continuity, and surface flatness of the adhesive layer are inspected using a combination of thickness gauge and visual sampling. Unqualified areas are locally repaired and recoated.

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