Additive Manufacturing Tool Paths for Continuous Carbon Fiber

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Solution Overview

Problem

In additive manufacturing, particularly 3D printing, fiber-reinforced thermoplastic filaments face structural integrity issues due to discontinuities when cut, leading to weakened material and potential failure under shearing forces, especially in articles with complex geometries and acute angles, where long uninterrupted filament runs are desirable but difficult to maintain.

Innovation Solution

The technique of filament feathering is employed, where tool paths are generated to strategically distribute the starting and ending points of filament segments, reducing the number of aligned discontinuities and short material runs by staggering filament ends and using edge-offsetting strategies to preserve continuity, thereby minimizing weak seams and enhancing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional additive manufacturing tool paths are used to fabricate articles with complex geometries and acute angles, then the article can be manufactured with the desired shape, but the filament is frequently cut and discontinued, leading to reduced structural integrity and weakened material strength

Engineering Contradiction:

Improvecomplex geometryVSAvoidstructural integrity

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The system performs preliminary analysis of the tool path to identify regions where filament discontinuities will occur, and proactively adjusts the tool path generation to stagger these discontinuities before they become aligned weak points in the final article

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extends the tool path optimization from two-dimensional layer planning to three-dimensional multi-layer coordination, distributing filament discontinuities across different spatial dimensions (different layers and horizontal positions) to prevent alignment and maintain structural integrity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the filament is cut into short segments to accommodate complex geometries and acute angles, then the article can be fabricated with the desired shape, but the number of discontinuities increases, creating more weak seams and reducing reliability

Engineering Contradiction:

Improvegeometric flexibilityVSAvoidresistance to failure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention accepts that filament discontinuities are inevitable for complex geometries, but converts this harmful necessity into a beneficial distributed pattern where discontinuities are strategically positioned to avoid alignment, thereby maintaining reliability while achieving geometric flexibility

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If traditional tool path generation is used without considering filament continuity, then the manufacturing process is simpler and faster, but aligned discontinuities create weak seams that reduce article strength and increase likelihood of failure

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidresistance to shearing force

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The system incorporates feedback mechanisms that analyze the generated tool path for patterns of aligned discontinuities and automatically adjust subsequent tool path generation to eliminate these weak points, creating a continuous improvement loop that maintains both efficiency and strength

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11084273B2Generating tool paths to preserve filament continuity in additive manufacturing

Publication Date: 2021.08.10 STRATASYS INC

AI summary

An article of manufacture is disclosed that comprises an infill made from linear segments of filament, such as but not limited to continuous carbon fiber-reinforced thermoplastic filament. Approaches to tool path generation are addressed in which material runs of filament are applied that distribute where cuts, beginning, or ends of segments occur or points where two ends of segments are fused or the like to preserve filament continuity by reducing the number of short segments. Aspects of one approach include identifying long edges and eliminating short edges which acute angles with long edges and utilizing a clipping outline as part of the process of determining start and end points of material runs.