Faceted AM Openings for Accurate Insert Placement
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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 tolerance, but existing additive manufacturing techniques often result in undersized holes that necessitate costly and time-consuming post-print machining, and STL file resolution improvements lead to increased file sizes without addressing fabrication 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 for accurate placement and reduced post-processing needs, using additive manufacturing to create parts with polygonal cross-sections that constrain inserts without requiring extensive reaming or machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to manufacture parts with holes, then manufacturing flexibility and complexity handling are improved, but hole accuracy and tolerance are worsened due to undersized internal features requiring post-processing
Solution Approach 1:
The patent applies preliminary action by pre-compensating for additive manufacturing tolerances during the CAD design phase. The opening geometry is intentionally designed with facets that account for expected print variations, so that after printing, the opening naturally constrains the insert within acceptable tolerances without requiring post-processing machining.
Solution Approach 2:
The patent changes the geometric parameters of the opening from traditional cylindrical shapes to polyhedral shapes with specific facet configurations. This parameter change allows the opening to accommodate additive manufacturing tolerances while still providing precise insert location, transforming the tolerance accumulation problem into a controlled geometric constraint system.
2Measurement precision
If STL file resolution is increased to improve part accuracy, then measurement precision is improved, but file size increases exponentially and fabrication inaccuracies are not addressed
Solution Approach 1:
The patent segments the opening surface into a finite number of planar facets rather than using continuous curved surfaces represented by dense triangle tessellations. This segmentation approach maintains adequate geometric accuracy for additive manufacturing while dramatically reducing the number of triangles needed in the STL file, thus reducing file size without sacrificing functional precision.
Solution Approach 2:
The patent changes the mathematical representation of the opening geometry from high-resolution continuous surfaces to lower-resolution polyhedral approximations with controlled facet counts. This parameter change recognizes that additive manufacturing inherently limits achievable precision, so ultra-fine STL resolution provides no practical benefit while consuming excessive memory and processing resources.
3Manufacturing precision
If post-print machining is performed to finish holes, then hole accuracy is improved, but production time and cost increase
Solution Approach 1:
The patent performs preliminary action by designing the opening geometry in advance to account for additive manufacturing tolerances and characteristics. The faceted opening is specifically configured to constrain inserts within acceptable tolerances directly from the printing process, eliminating the need for subsequent machining operations and thereby maintaining high production speed.
Solution Approach 2:
The patent applies self-service by designing the opening to self-constrain the insert through its faceted geometry. The tangent facets naturally locate and constrain the insert without requiring external machining intervention, allowing the part to achieve its functional requirements through the additive manufacturing process alone.
4Ease of manufacture
If traditional cylindrical openings are used in additively manufactured parts, then ease of manufacture is maintained, but insert location accuracy is worsened due to tolerance accumulation
Solution Approach 1:
The patent applies asymmetry by transitioning from symmetric cylindrical openings to asymmetric polyhedral openings with specific facet arrangements. This asymmetric geometry provides deterministic constraint points (tangent facets) that prevent rotational and positional variability of the insert, thereby improving location accuracy while remaining manufacturable through additive processes.
Solution Approach 2:
The patent performs preliminary action by pre-configuring the opening geometry with specific facet orientations and positions that will naturally constrain the insert in the desired location after printing. This preliminary geometric design compensates for additive manufacturing tolerances and ensures accurate insert placement without requiring post-processing adjustment.
Data Source
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.