CAD Geometry Filtering for Support-Free 3D Manufacturing
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Solution Overview
Problem
Existing CAD software struggles to generate 3D models that are well-suited for additive manufacturing, particularly in reducing or eliminating the need for support structures, which complicates and increases the cost of the manufacturing process.
Innovation Solution
A computer-aided design method that modifies 3D shapes by offsetting two-dimensional profiles based on manufacturing process constraints, such as overhang angles, to reduce or eliminate the need for support structures, using techniques like generative design and level-set representations to optimize geometry for additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If generative design is used to create optimized 3D geometry, then design objectives are met and material efficiency is improved, but the resulting geometry often requires support structures that complicate manufacturing
Solution Approach 1:
The patent applies preliminary action by performing geometry filtering during the generative design process itself, rather than as a separate post-processing step. The level-set method modifies the generated geometry to preemptively eliminate features that would require support structures, ensuring the design is manufacturing-ready from the outset.
Solution Approach 2:
The patent changes geometric parameters by applying filters that modify surface angles and overhang characteristics. The level-set method adjusts the geometry parameters to ensure all surfaces meet manufacturability criteria (e.g., maximum overhang angle constraints) while preserving the optimized material distribution.
2Weight of moving object
If complex optimized geometry is generated to minimize weight and material, then design performance is improved, but support structures must be added which increase manufacturing complexity and cost
Solution Approach 1:
The patent extracts and removes problematic geometric features that would require support structures. The level-set filtering process identifies and eliminates overhanging surfaces and sharp features, keeping only the essential optimized geometry that meets both performance and manufacturability requirements.
Solution Approach 2:
Instead of adding support structures to enable manufacturing of complex geometry, the patent inverts the approach by modifying the geometry itself to be manufacturable without supports. The level-set method transforms the optimized but unsupported geometry into a self-supporting design.
3Loss of substance
If generative design creates optimized surfaces, then material efficiency is improved, but surface quality may deteriorate due to tiny features and sharp angles
Solution Approach 1:
The patent applies local quality by selectively filtering only specific geometric features (overhangs, sharp angles, tiny features) while preserving the overall optimized geometry and surface quality in critical areas. The level-set method applies different filtering intensities to different regions based on local manufacturability requirements.
Solution Approach 2:
The patent applies curvature by rounding sharp features and eliminating angular surfaces through the level-set filtering process. The method smooths out problematic geometric features while maintaining the essential shape and material efficiency of the generatively designed part.
Data Source
AI summary
Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using techniques that facilitate manufacturing, include: modifying a three dimensional shape, for which a corresponding physical structure is to be created using a manufacturing process, to produce a modified three dimensional shape; and providing the modified shape of the modeled object for use in manufacturing the physical structure using one or more computer-controlled manufacturing systems that employ the manufacturing process. The modifications can include, for each of two or more discrete layers of the three dimensional shape along a direction associated with the manufacturing process, extracting a two dimensional profile representation of the three dimensional shape in a current discrete layer, offsetting the two dimensional profile representation by an amount associated with the manufacturing process, and changing a next discrete layer using an offset two dimensional profile representation of the current discrete layer.