3D Mesh Shape Modification for Self-Supporting Overhangs

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Solution Overview

Problem

Additive manufacturing (AM) processes face challenges in producing parts with unsupported downward-facing surfaces due to the need for sacrificial support structures, which increase fabrication costs and time, and existing methods often fail to address this issue effectively.

Innovation Solution

A geometry modification algorithm that modifies 3D object models to eliminate overhangs by minimizing the need for sacrificial material, using a gradient descent algorithm with regularization terms to ensure topological validity and self-supporting structures, allowing for near-net shape production without additional support structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sacrificial support structures are introduced to support unsupported downward-facing surfaces, then the part can be manufactured with complex geometries, but material costs and fabrication time increase

Engineering Contradiction:

Improvemanufacturability of complex geometriesVSAvoidmaterial costs

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent extracts and removes the sacrificial support structures from the final part after additive manufacturing. The support structures are designed to be temporary and are completely removed post-fabrication, leaving only the functional part geometry without unnecessary material

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary shaping of the part during the additive manufacturing process itself, using the build process to create the final geometry without requiring subsequent support structures. The part is manufactured in a near-net shape that eliminates the need for additional support material

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If sacrificial support structures are introduced to support unsupported downward-facing surfaces, then the part can be manufactured with complex geometries, but clean-up time increases

Engineering Contradiction:

Improvemanufacturability of complex geometriesVSAvoidclean-up time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Inventive Principle:

Principle #10Preliminary action

3Loss of substance

If the 3D object model is modified to eliminate overhangs, then sacrificial material is minimized, but the original design geometry is altered

Engineering Contradiction:

Improvesacrificial materialVSAvoidoriginal design geometry

Core Design Contradiction:

Loss of substanceVSShape

Solution Approach 1:

The patent applies local modifications only to specific regions of the 3D model that contain overhangs exceeding the threshold angle. The optimization algorithm identifies and modifies only the necessary local areas while preserving the overall design geometry and functional features of the part

Inventive Principle:

Principle #3Local quality

4Device complexity

If the overhang angle threshold is set lower, then fewer modifications are needed, but more sacrificial material is required

Engineering Contradiction:

Improvemodification complexityVSAvoidsacrificial material

Core Design Contradiction:

Device complexityVSLoss of substance

Solution Approach 1:

The patent uses an optimized overhang angle threshold parameter that balances modification complexity and sacrificial material requirements. The threshold is set based on the specific additive manufacturing process capabilities, allowing sufficient geometric modification to reduce support material while maintaining practical manufacturability

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12430852B2Shape modification for self-supporting structures in additive manufacturing

Publication Date: 2025.09.30 XEROX CORP

AI summary

This disclosure teaches techniques, devices, and systems for automatically modifying a 3-Dimensional (3D) object model. The apparatus comprising a memory and a processing device coupled to the memory. The processor and the memory are configured to obtain an input 3D object model comprising an input 3D mesh, analyze the input 3D mesh to identify unprintable overhangs that have an angle over an overhang angle limit and identify vertices associated with the unprintable overhangs as active vertices, and perform an optimization process to move the active vertices to eliminate the unprintable overhangs and generate a modified 3D mesh. The optimization process includes a gradient descent search algorithm performed on an objective function comprising a cost function configured to minimize a difference between the input 3D mesh and the modified 3D mesh subject to an overhang constraint related to the overhang angle limit.