Generative 3D Modeling for 2.5-Axis Milling Constraints

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Solution Overview

Problem

Existing computer-aided design (CAD) software struggles to efficiently generate three-dimensional models that are optimized for 2.5-axis subtractive manufacturing processes, as these processes require specific geometries and milling directions that current methods do not adequately address.

Innovation Solution

The development of a method within CAD software that uses density-based representations and topology optimization to iteratively modify three-dimensional shapes, adjusting density values and layer boundaries in accordance with the milling direction of the 2.5-axis subtractive manufacturing process, thereby producing designs compatible with 2.5-axis machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CAD software generates 3D models using standard boundary representation (B-Rep) formats, then the models achieve smooth and precise mathematical surfaces, but the models are difficult to manufacture using 2.5-axis subtractive manufacturing processes

Engineering Contradiction:
Improvemodel precisionVSAvoidmanufacturability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the continuous B-Rep model into discrete volumetric elements (tetrahedral or hexahedral meshes). This segmentation transforms the smooth mathematical surfaces into discrete geometric units that can be systematically processed by 2.5-axis manufacturing systems, enabling layer-by-layer material removal while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a manufacturing-specific dimension by transforming the traditional 3D B-Rep model into a volumetric representation with explicit layer boundaries. This dimensional transformation adds manufacturing process information (layer depth, milling direction) to the geometric model, making it compatible with 2.5-axis subtractive manufacturing constraints.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple CNC machine cutting tools are used in series operations for subtractive manufacturing, then complex 3D objects can be created from stock material, but the manufacturing time and process complexity increase significantly

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs preliminary action by pre-defining layer boundaries and milling directions in the 3D model during the design phase. This preliminary structuring of the model into manufacturable layers eliminates the need for complex real-time toolpath planning and multiple cutting tool operations, significantly reducing manufacturing time while maintaining design flexibility.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If B-Rep models are sampled and replaced with volumetric representations for physical simulations, then the simulations become more convenient and efficient, but the exact surface boundary representation is lost

Engineering Contradiction:
Improvesimulation efficiencyVSAvoidsurface precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by maintaining different representation qualities in different regions of the model. The internal volumetric elements use discrete meshes for efficient simulation, while the external surface boundaries preserve exact B-Rep mathematics for manufacturing precision. This dual-quality approach ensures both simulation efficiency and surface accuracy are maintained.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4154156B1Computer aided generative design with layer boundary determination to facilitate 2.5-axis subtractive manufacturing processes
Publication Date: 2025.02.19 AUTODESK INC
  • EP4154156B1 patent drawingFigure 1A
  • EP4154156B1 patent drawingFigure 1B
  • EP4154156B1 patent drawingFigure 2

AI summary

Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using generative design processes, where the 3D models of the physical structures are produced so as to facilitate manufacturing of the physical structures using 2.5-axis subtractive manufacturing systems and techniques, include: obtaining a design space, design criteria, and in-use case(s); iteratively modifying a generatively designed shape in the design space in accordance with the design criteria and the in-use case(s) using a density-based representation of the generatively designed shape and including adjusting the density-based representation of the generatively designed three dimensional shape in accordance with a milling direction of a 2.5-axis subtractive manufacturing process in at least two iterations of the iteratively modifying; and providing the generatively designed shape for use in manufacturing a physical structure using computer-controlled manufacturing that employs the 2.5-axis subtractive manufacturing process.