Optical Direction Modifiers in Additive Manufacturing Feedstock Lines

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Solution Overview

Problem

In 3D printing processes using photopolymers with reinforcing fibers, the opacity of fibers to curing energy prevents uniform curing due to shadowing effects, leading to incomplete or uneven curing of the resin.

Innovation Solution

Incorporating optical direction modifiers within the feedstock line, which redirect electromagnetic radiation to penetrate and cure the resin in shadowed regions, ensuring more even and thorough curing by scattering or dispersing the radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcing fibers are added to photopolymer feedstock material, then mechanical strength and structural integrity are improved, but uniform curing of the resin is worsened due to shadowing effects from opaque fibers

Engineering Contradiction:
Improvemechanical strengthVSAvoidcuring uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

Optical direction modifiers act as intermediary elements between the curing energy source and the resin-fiber composite. These modifiers redirect electromagnetic radiation around the opaque fibers to reach shadowed resin regions, enabling uniform curing while maintaining fiber reinforcement. The modifiers serve as a mediating mechanism that resolves the conflict between fiber opacity and curing completeness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If direct electromagnetic radiation is used to cure photopolymer resin, then curing speed is improved, but complete curing in shadowed regions is worsened due to fiber obstruction

Engineering Contradiction:
Improvecuring speedVSAvoidcuring completeness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The optical direction modifiers introduce a spatial redistribution of curing energy by redirecting radiation in multiple directions. Instead of direct line-of-sight curing that is blocked by fibers, the modifiers scatter and redirect energy around obstacles, adding dimensional complexity to the radiation path and enabling curing in previously inaccessible shadowed regions.

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

3Strength

If opaque reinforcing fibers are used in photopolymer feedstock, then structural reinforcement is improved, but electromagnetic radiation penetration is worsened

Engineering Contradiction:
Improvestructural reinforcementVSAvoidradiation penetration
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The optical direction modifiers are distributed locally throughout the feedstock material at specific concentrations and positions. This local distribution creates zones of radiation redirection throughout the composite structure, allowing energy to penetrate and cure resin in shadowed regions while maintaining the structural integrity provided by the fiber reinforcement network.

Inventive Principle:
Principle #3Local quality

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

The solution allows for more efficient, uniform, and rapid curing of the resin within the feedstock line, even in areas obscured by reinforcing fibers, enhancing the additive manufacturing process, particularly in fused filament fabrication.

Implementation Method 1

Each of the optical direction modifiers is configured such that when electromagnetic radiation strikes the outer surface from a first direction, at least a portion of the electromagnetic radiation departs the outer surface in a second direction that is at an angle to the first direction

Methodology Applied
Scientific EffectElectromagnetic radiation redirection: Reflection

Implementation Method 2

the optical direction modifiers will redirect the electromagnetic radiation to disperse or scatter the electromagnetic radiation to indirectly reach regions of the resin

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

When the polymer in the feedstock material is a photopolymer, a source of curing energy may be directed at the feedstock material, dispensed by the print head, to solidify the feedstock material

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3689584B1Feedstock lines for additive manufacturing of an object, and systems and methods for creating feedstock lines
Publication Date: 2023.04.05 THE BOEING CO
  • EP3689584B1 patent drawingFigure 1
  • EP3689584B1 patent drawingFigure 2
  • EP3689584B1 patent drawingFigure 3

AI summary

A feedstock line (100) comprises elongate filaments (104), a resin (124), and optical direction modifiers (123). The resin (124) covers the elongate filaments (104). The optical direction modifiers (123) are covered by the resin (124) and are interspersed among the elongate filaments (104). Each of the optical direction modifiers (123) has an outer surface (184). Each of the optical direction modifiers (123) is configured such that when electromagnetic radiation (118) strikes the outer surface (184) from a first direction, at least a portion of the electromagnetic radiation (118) departs the outer surface (184) in a second direction that is at an angle to the first direction to irradiate, in the interior volume of the feedstock line (100), the resin (124) that, due at least in part to the elongate filaments (104), is not directly accessible to the electromagnetic radiation (118), incident on the exterior surface of the feedstock line.