Graph-Based Stereolithography Support Structure Design
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Solution Overview
Problem
Existing stereolithography methods for defining supporting structures often result in either undersized or oversized structures, leading to inefficiencies in production time, material usage, and cleaning difficulties due to their independence from the three-dimensional object's geometry.
Innovation Solution
A method using graph theory to define a connected acyclic graph for selecting pairs of supporting elements and reinforcing elements, ensuring a stable structure with minimized volume, which is tailored to the object's specific needs by generating a minimum spanning tree and optimizing the placement of reinforcing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predefined grid is used to define the supporting structure independently of the object geometry, then the structure provides general support coverage, but the volume becomes excessively large leading to increased production time and material consumption
Solution Approach 1:
The supporting structure is designed with non-uniform properties: the grid density and element thickness vary locally based on the actual support needs of different regions of the three-dimensional object. Areas requiring stronger support have denser or thicker grid elements, while areas needing less support have sparser or thinner elements, optimizing both reliability and volume reduction.
Solution Approach 2:
The invention changes the parameters of the supporting structure (grid density, element thickness, spacing) based on the object's geometry and support requirements. By dynamically adjusting these parameters rather than using a fixed predefined grid, the structure achieves optimal support with minimized volume.
2Strength
If a thicker grid is used to ensure structural stability, then the supporting strength increases, but the volume increases and cleaning operations are hindered
Solution Approach 1:
The grid thickness is varied locally throughout the supporting structure. Thicker elements are placed only where structurally necessary to prevent collapse, while thinner elements are used in regions with lower support requirements. This local differentiation maintains overall strength while significantly reducing total volume and improving cleaning access.
3Ease of manufacture
If a predefined grid is used for the supporting structure, then the definition process is simplified, but the structure does not optimally match the object's specific structural needs
Solution Approach 1:
The method performs preliminary analysis of the three-dimensional object's geometry and identifies regions requiring support before generating the supporting structure. This preliminary action allows the system to automatically configure an optimized grid that matches actual structural needs while maintaining automated generation and relatively simple definition processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a supporting structure that is optimally sized, reducing production time, material consumption, and facilitating easier washing of the three-dimensional object by minimizing the overall volume while maintaining structural stability.
Implementation Method 1
Each layer of the object is obtained through solidification of a material in the liquid or paste state, which occurs through selective exposure to light radiation. Typically, the material is a plastic-based compound that polymerizes when it is reached by said light radiation.
Data Source
AI summary
The invention is a computer-implemented method for defining a supporting structure (2) for a three-dimensional object (1) to be produced through a stereolithography process, comprising the following operations: defining a first surface (3) to be supported of the three-dimensional object (1) and a second surface (4) facing the first surface (3); defining elongated supporting elements (5) between the surfaces (3, 4); defining pairs of supporting elements (5); for each pair of supporting elements (5), defining an elongated reinforcing element (6) connecting the two supporting elements (5) of the pair. The definition of the pairs of supporting elements (5) comprises the following operations: defining a reference point (7) of each supporting element (5); defining a connected acyclic graph (8) having as vertices the reference points (7); for each edge (9) of the graph, defining one pair of supporting elements comprising the two supporting elements (5) corresponding to the ends of the edge (9). The definition of the pairs of supporting elements (5) comprises the further operation of defining an additional pair of supporting elements for each vertex having order 1 of the connected acyclic graph (8), the additional pair comprising a first supporting element (5) corresponding to the vertex having order 1 and a second supporting element (5) not connected to the first supporting element (5) through any edge (9).