Aircraft Fastener Hole Assembly with Pre-Chamfered Burr Prevention
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Solution Overview
Problem
Current aircraft assembly methods require disassembly and manual de-burring to align and chamfer fastener openings, leading to increased manufacturing costs and time due to burr formation during drilling.
Innovation Solution
A method involving drilling initial openings with a first diameter, forming chamfers, and then aligning members using determinate assembly features to drill the openings to a larger second diameter, where the chamfers are formed at a diameter greater than the second diameter, preventing burr formation and eliminating the need for disassembly and de-burring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If components are assembled together and a single hole is drilled through the stack to ensure alignment, then alignment accuracy is improved, but burrs are formed between adjacent components leading to stress points and decreased service life
Solution Approach 1:
The patent applies preliminary action by forming chamfers on the first and second members before assembling them together. These pre-formed chamfers prepare the openings to receive the fastener, preventing burr formation during the subsequent drilling operation while maintaining alignment accuracy through determinate assembly features.
Solution Approach 2:
The patent converts the potential harm of burr formation into a benefit by using the drilling operation to enlarge already-chamfered openings. The determinate assembly features ensure precise alignment while the chamfers protect against burr formation, turning a problematic process into a beneficial one that eliminates manual de-burring.
2Object-generated harmful factors
If the stack of components is disassembled after drilling to manually de-burr the drilled openings and form chamfers, then burr formation is prevented, but manufacturing costs and manufacturing time increase
Solution Approach 1:
The patent performs the chamfering action before assembly and drilling, rather than after. By forming chamfers on individual members before they are assembled and drilled together, the process prevents burr formation without requiring subsequent disassembly and manual de-burring operations, thereby maintaining high productivity.
Solution Approach 2:
The patent inverts the traditional sequence of operations. Instead of drilling first and then chamfering/de-burring, it chamfers first and then drills to enlarge the openings. This reversal eliminates the need for disassembly and manual de-burring, reducing manufacturing time and costs.
3Duration of action of stationary object
If manual de-burring and chamfering is performed after drilling, then service life of components is improved, but manufacturing costs increase
Solution Approach 1:
The patent forms chamfers on the members before assembly and drilling, preparing the openings in advance to prevent burr formation. This preliminary chamfering protects the components from stress points and extends service life without requiring costly manual de-burring operations afterward.
Solution Approach 2:
The patent converts the drilling operation that would normally create harmful burrs into a beneficial process that enlarges pre-chamfered openings. The determinate assembly features ensure precise alignment while the chamfers prevent burr formation, eliminating the need for costly manual de-burring while extending component service life.
4Manufacturing precision
If determinate assembly features are used to position members during assembly, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The patent uses determinate assembly features that are integrally formed on the members themselves, allowing the components to self-align during assembly. These features enable precise positioning and alignment without requiring external tooling or complex assembly equipment, maintaining ease of manufacture while achieving high alignment precision.
Data Source
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AI summary
A method of assembling an aircraft assembly including a first member (102) and a second member (104) includes drilling a first opening (110) through the first member, the first opening having a first diameter, and drilling a second opening (122) through the second member, the second opening having the first diameter. The method also includes forming a first chamfer (116) on the first opening and forming a first chamfer (128) on the second opening, the first chamfer on the first opening and the first chamfer on the second opening having a chamfer diameter. The method also includes positioning the first member and the second member to align the first opening and the second opening, and drilling the first opening and the second opening to a second diameter, wherein the second diameter is greater than the first diameter.