Native CAD Slicing for Additive Manufacturing Precision
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Solution Overview
Problem
Current additive manufacturing (AM) processes are inefficient and prone to errors when using triangulated stereolithography (STL) files, which can result in low-quality meshes and inaccuracies, especially for objects with non-linear features, leading to time-consuming re-meshing and potential material waste.
Innovation Solution
A system and method for generating CAD design slice files directly from native or neutral CAD geometries, eliminating the need for STL files by computing the intersection of the build-slice plane with the CAD model, allowing for improved resolution and accuracy in the slicing process, and enabling the retention of metadata for verification and validation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If triangulated STL files are used for additive manufacturing, then the slicing process can be performed, but the mesh quality is low and contains thousands of errors that adversely affect the AM process
Solution Approach 1:
The patent extracts and eliminates the problematic intermediate STL triangulation step from the workflow. By directly importing native CAD geometries and slicing them without converting to triangulated meshes, the source of mesh errors is removed entirely, achieving both high precision and reliability
Solution Approach 2:
The patent introduces a new intermediary format (AMF or custom slice file format) that preserves exact CAD geometry information while enabling slicing operations. This intermediary serves as a bridge between CAD systems and AM machines without requiring lossy triangulation
2Measurement precision
If linear triangles are used to approximate non-linear CAD features, then the model can be processed, but the accuracy is reduced and refinement is no longer possible
Solution Approach 1:
Instead of approximating curved surfaces with flat triangles (the conventional approach), the patent inverts the approach by using exact parametric CAD representations that can represent non-linear features precisely. The slicing plane intersects the parametric surfaces directly, generating accurate intersection curves without triangulation
Solution Approach 2:
The patent changes the mathematical representation from discrete linear triangles to continuous parametric surfaces with adjustable resolution. This allows the model to maintain exact representation of non-linear features while enabling refinement by adjusting slicing parameters without re-meshing
3Productivity
If auto-generation of triangle meshes is performed, then the slicing process can proceed, but thousands of errors are introduced that require time-consuming fixing
Solution Approach 1:
The patent performs preliminary validation of CAD geometry integrity before slicing, and generates error-free slice files directly from validated CAD models. By ensuring geometry correctness upfront and avoiding error-prone triangulation, no time-consuming error fixing is required later
Solution Approach 2:
The patent removes the error-generating triangle mesh generation step from the workflow entirely. By slicing directly from native CAD geometries, the source of mesh errors is eliminated, and the process becomes both faster and more reliable
4Reliability
If STL files are converted and fixed before slicing, then the mesh can be used, but the process takes an hour or more which significantly slows the AM process
Solution Approach 1:
The patent extracts and eliminates the time-consuming mesh conversion and fixing steps by implementing direct slicing from native CAD geometries. This removes the bottleneck entirely, achieving both reliability and speed
Solution Approach 2:
The patent replaces the mechanical mesh manipulation process (converting, fixing, and refining triangles) with a direct mathematical intersection approach between slicing planes and parametric CAD surfaces, which is computationally more efficient and produces correct results directly
5Adaptability or versatility
If standard slice file formats are used, then the files can be processed by AM machines, but curved surfaces cannot be accurately represented
Solution Approach 1:
The patent uses a composite approach by combining exact parametric surface representations with discrete slicing layers. The slice files contain both the precise intersection curves (preserving curvature information) and the layer-by-layer instructions, enabling both accuracy and machine compatibility
Solution Approach 2:
The patent enhances standard slice file formats by incorporating parametric surface definitions and basis function information, allowing curved surfaces to be accurately represented while maintaining compatibility with AM machine processing through extended data structures
Data Source
AI summary
A system and method for improving the production of objects with fully defined CAD models by generating CAD slice files from the native CAD geometries for use by AM machines. An electronic processing element receives the CAD model having a native and/or neutral format with metadata, determines a desired resolution, slices the CAD model to create the slice files having a slice format (e.g., point, edge, surface, volume) and retaining the metadata, and evaluates the slice files to determine whether the resolution has been achieved. If so, the slice files are sent to the AM machine. If not, a new desired resolution is determined and the CAD model is re-sliced, which may include combining the slice files to regenerate the CAD model. A support structure for the object may be analyzed, and if distortion is predicted, a modified CAD model may be created and sliced to create modified slice files.