Systems and methods for generating a shape-based graded lattice structure and their application to additive manufacturing
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Solution Overview
Problem
Current additive manufacturing technologies struggle to generate non-uniform lattice structures that account for varying stress or thermal fields, leading to inefficiencies in material usage and structural integrity due to uniform thickness changes and nozzle movement disruptions.
Innovation Solution
A method for generating non-uniform graded lattice infill structures based on a physical field, using circle-packing algorithms and field-tailored lattice generation to create structures with varying cell sizes and transition zones, ensuring connectivity and adaptability to stress or thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If uniform lattice structures are used in additive manufacturing, then manufacturing simplicity is maintained, but structural performance under varying stress fields is insufficient
Solution Approach 1:
The patent applies local quality by varying the lattice unit cell size based on the stress field distribution. High-stress regions receive smaller unit cells for enhanced strength, while low-stress regions use larger unit cells to reduce material usage. This is achieved through a workflow that incorporates stress field analysis and automatically generates non-uniform lattice structures with spatially varying cell dimensions, thereby optimizing structural performance without uniform complexity throughout.
2Strength
If simple functionally graded structure approaches are used with local wall thickness changes, then stress field consideration is partially addressed, but manufacturing disruptions occur due to nozzle movement
Solution Approach 1:
The patent segments the lattice structure into discrete unit cells with standardized dimensions that are multiples of the nozzle diameter. This segmentation allows the lattice to be generated as a series of regular, manufacturable units rather than continuous variable thickness walls. The stress field is discretized into zones with different unit cell sizes, enabling both stress adaptation and manufacturing continuity without nozzle disruption.
Solution Approach 2:
The patent introduces a transition zone between regions of different unit cell sizes that dynamically adapts the lattice configuration. This transition zone uses a mix of unit cell types and varying densities to smoothly connect high-stress and low-stress regions, maintaining structural integrity and enabling continuous manufacturing without abrupt changes that would disrupt nozzle movement.
3Strength
If non-uniform lattice structures with varying unit sizes are generated, then stress field adaptation is improved, but manufacturing connectivity is compromised
Solution Approach 1:
The patent changes the parameter of unit cell size in a controlled manner based on stress field intensity. Unit cell dimensions are varied as discrete steps rather than continuous changes, with each size being a multiple of the nozzle diameter. This parameter change strategy maintains lattice connectivity by ensuring that adjacent unit cells can be manufactured with consistent material deposition, while still adapting to the stress field through size variation.
Data Source
AI summary
Systems and methods for generating a shape-based graded lattice structure that can be used in additive manufacturing. A slicer computer system generates the lattice structure by simulating the packing of a planar region with variable-sized packing shapes, where packing shape sizes correspond to intensity values of a non-uniform physical field expected to be experienced by the article. An intermediate lattice structure is then generated using a first set of polygonal cells, followed by a second set of polygonal cells that refine the final lattice structure. Tailored sectioning and field-based smoothing can modify polygon packing algorithms to adapt lattice generation. The resultant multi-stage graded lattice structures, which may include multiple lattice patches and transition zones, from shape-based packing, tailored sectioning, field-based smoothing, and slicer-based additive manufacturing processing improve connectivity and manufacturability over traditional lattice structures.