Boundary Curve Alignment for 2.5-Axis Milling Height Layers

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Solution Overview

Problem

Current CAD software limitations in generating 3D geometry for 2.5-axis subtractive manufacturing, as they often require manual intervention and are inefficient in handling discrete height layers and milling directions, leading to increased CAM programming time and potential manufacturing issues like undercuts and thin shelves.

Innovation Solution

A boundary-based generative design process that uses level-set methods to optimize 3D models for 2.5-axis subtractive manufacturing, incorporating manufacturability constraints to guide shape changes towards discrete height layers and milling directions, thereby facilitating the creation of flat areas and reducing manufacturing complexities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If boundary-based generative design with manufacturability constraints is implemented, then manufacturing precision and ease of manufacture are improved, but device complexity increases

Engineering Contradiction:
Improvegeometry precision for 2.5-axis manufacturingVSAvoidsoftware process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The generative design process is segmented into distinct phases: initial geometry generation, manufacturability constraint application, and post-processing. Each phase handles specific aspects of the design, making the complex overall process more manageable and systematic

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Manufacturability constraints are applied during the generative design process itself rather than as a separate post-processing step. This preliminary application of constraints ensures that geometry is generated with manufacturing considerations built-in, reducing later complexity

Inventive Principle:
Principle #10Preliminary action

2Productivity

If manual intervention is used in current CAD software for 2.5-axis manufacturing, then ease of operation is maintained, but productivity decreases

Engineering Contradiction:
ImproveCAM programming speedVSAvoidsoftware usability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system automatically generates manufacturable geometry with appropriate flat areas and height layers without requiring manual user intervention. The generative design solver self-adjusts the geometry to meet 2.5-axis manufacturing requirements, significantly improving productivity while maintaining ease of use through automated processes

Inventive Principle:
Principle #25Self-service

3Shape

If smooth boundary curves are used in generative models, then shape quality is improved, but manufacturing difficulty increases due to lack of flat areas

Engineering Contradiction:
Improvecurve smoothnessVSAvoid2.5-axis manufacturability
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The geometry exhibits different qualities in different regions: smooth curved surfaces in areas where precision is critical, and flat planar areas in regions requiring 2.5-axis manufacturing. This local differentiation allows the model to satisfy both aesthetic/functional requirements and manufacturing constraints simultaneously

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system transitions from purely smooth 3D curves to surfaces with discrete height layers and flat areas. By introducing the dimension of height layering, the geometry can maintain smoothness in horizontal planes while creating manufacturable flat surfaces at different elevations

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

4Ease of manufacture

If discrete height layers are enforced in generative design, then ease of manufacture is improved, but manufacturing precision may worsen due to geometry approximation

Engineering Contradiction:
Improve2.5-axis manufacturing simplicityVSAvoidgeometry accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system applies discrete height layers selectively rather than uniformly across the entire geometry. Flat areas are created only where required by 2.5-axis manufacturing constraints, while other regions maintain higher precision smooth surfaces, achieving a balance between manufacturability and accuracy

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4224354A1Aligning smooth boundary curves of height layers for 2.5-axis subtractive manufacturing
Publication Date: 2023.08.09 AUTODESK INC
  • EP4224354A1 patent drawingFigure 1A
  • EP4224354A1 patent drawingFigure 1B
  • EP4224354A1 patent drawingFigure 2A~2B

AI summary

Method, systems, and medium for removing narrow shelves between smooth contours of layers of a CAD object to be produced with a 2.5-axis subtractive manufacturing process by: - Detecting almost coincident smooth boundary curves of different height layers, - replacing a portion of one curve with a portion of the second curve (thus aligning the curves), - rendering and allowing the user to modify parametric history of the part model - providing the part model for use in manufacturing.