Faceted AM Openings for Accurate Insert Holes Without Reaming
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Solution Overview
Problem
Current methods for manufacturing holes in structural parts for fasteners, such as those used in aircraft, require high accuracy and tight tolerances, but existing additive manufacturing techniques often result in undersized holes that necessitate costly and time-consuming post-print machining to achieve the required dimensions, and the resolution of STL files can lead to inaccuracies.
Innovation Solution
The method involves forming openings with internal surfaces comprising a plurality of facets, where the facets are tangent to the insert's outer contact surface, allowing the insert to be accurately located with minimal post-processing, using additive manufacturing to create parts with polygonal cross-sections that constrain the insert, and generating data files that accurately represent these facets to ensure precise manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing is used to manufacture parts with holes, then manufacturing flexibility and complexity handling are improved, but hole accuracy and dimensional precision deteriorate due to undersized features and printer inaccuracies
Solution Approach 1:
The patent applies preliminary action by pre-compensating for printer inaccuracies and undersized features during the CAD modeling stage. The hole geometry is intentionally designed with compensation factors built-in before manufacturing, so that the final printed dimensions achieve the desired accuracy without requiring post-processing machining operations.
Solution Approach 2:
The patent changes the geometric parameters of the hole features in the digital model to account for additive manufacturing characteristics. By adjusting hole sizes, wall thicknesses, and other dimensional parameters during design, the patent compensates for expected printing inaccuracies and ensures the final part meets tolerance requirements.
2Manufacturing precision
If post-print machining is used to finish holes, then hole accuracy and dimensional precision are improved, but production time and manufacturing cost increase
Solution Approach 1:
The patent applies self-service by designing the part and tool features to be self-mating with built-in compensation for manufacturing tolerances. The interlocking geometry and tolerance zones are designed so that the parts assemble correctly without requiring additional machining operations, making the manufacturing process self-sufficient.
Solution Approach 2:
The patent performs preliminary compensation for tolerances and dimensional variations during the design phase, eliminating the need for subsequent machining operations. By building in tolerance compensation and self-mating features beforehand, the patent achieves high accuracy directly from additive manufacturing.
3Manufacturing precision
If STL file resolution is increased to improve part accuracy, then manufacturing precision is improved, but file size increases exponentially
Solution Approach 1:
The patent applies local quality by applying high-precision geometry only where it is critically needed for functionality, such as at mating surfaces and hole locations. Other portions of the part can use coarser meshing, thereby maintaining accuracy where required while keeping the overall file size manageable.
Data Source
Figure 1A~2
Figure 3A~3C
Figure 4A~4C
AI summary
A method of manufacturing a part having an opening for receiving an insert, including forming the opening having an internal surface wherein the internal surface has a polygonal cross-section including a plurality of sides. The polygonal cross-section comprises a polygon having an area larger than a cross-section of the insert, and the sides constrain the insert so as to locate the insert in the opening when the insert is inserted into the opening.