Optical Waveguide Feedstock for Uniform Photopolymer Curing

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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, leading to incomplete or uneven polymer solidification.

Innovation Solution

Incorporating a full-length optical waveguide within the feedstock line that is covered by resin, allowing electromagnetic radiation to penetrate and cure the resin even in areas shaded by the fibers, through its end faces or peripheral surface.

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 the fibers cast shadows that prevent uniform curing of the photopolymer

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

Solution Approach 1:

The patent introduces a second light source positioned below the build platform, irradiating the feedstock line from the bottom dimension. This dual-directional approach (top and bottom light sources) enables uniform curing of the photopolymer throughout the feedstock line, including regions shadowed by reinforcing fibers when viewed from a single direction.

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

2Productivity

If direct electromagnetic radiation is used to cure the photopolymer, then the curing process is simple and rapid, but the radiation cannot penetrate shadowed regions blocked by opaque fibers

Engineering Contradiction:
Improvecuring speedVSAvoidcuring completeness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

By adding a bottom light source that irradiates from the opposite direction, the system achieves complete curing without compromising speed. The dual-directional illumination ensures that radiation reaches all regions of the photopolymer, including those shadowed from the top view, thereby maintaining rapid curing while achieving complete penetration.

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

Solution Approach 2:

The patent uses the build platform and support structures as intermediaries to redirect and distribute electromagnetic radiation. The radiation reflects off these surfaces to reach shadowed regions, acting as a mediator that distributes curing energy uniformly throughout the feedstock line.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If the feedstock line contains opaque reinforcing fibers, then the mechanical properties of the manufactured object are enhanced, but the electromagnetic radiation cannot reach interior regions of the feedstock line

Engineering Contradiction:
Improvemechanical propertiesVSAvoidradiation penetration
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The bottom light source irradiates from the opposite direction, enabling radiation to penetrate the feedstock line through the reinforcing fibers from below. This dual-directional approach ensures that interior regions receive sufficient energy for complete curing while maintaining the structural integrity provided by the fibers.

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

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

Ensures more even, thorough, and rapid curing of the resin within the feedstock line, suitable for additive manufacturing techniques like fused filament fabrication.

Implementation Method 1

At least the one full-length optical waveguide comprises a full-length optical core. The full-length optical core comprises a first full-length-optical-core end face, a second full-length-optical-core end face, opposite the first full-length-optical-core end face, and a full-length peripheral surface, extending between the first full-length-optical-core end face and the second full-length-optical-core end face.

Methodology Applied
Scientific EffectOptical waveguide: Waveguide (optics)

Implementation Method 2

when electromagnetic radiation enters the full-length optical core via at least one of the first full-length-optical-core end face, the second full-length-optical-core end face, or the full-length peripheral surface, at least a portion of the electromagnetic radiation exits the full-length optical core via the full-length peripheral surface to irradiate, in the interior volume of the feedstock line, the resin

Methodology Applied
Scientific EffectElectromagnetic radiation transmission: Light

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

PatentEP3456514B1Feedstock lines for additive manufacturing of an object
Publication Date: 2021.07.28 THE BOEING CO
  • EP3456514B1 patent drawingFigure 1
  • EP3456514B1 patent drawingFigure 2
  • EP3456514B1 patent drawingFigure 3

AI summary

A feedstock line (100) comprises elongate filaments (104), a resin (124), and a full-length optical waveguide (102), comprising a full-length optical core (110). The full-length optical waveguide (102) is configured such that when electromagnetic radiation (118) enters the full-length optical core (110) via at least one of a first full-length-optical-core end face (112), a second full-length-optical-core end face (114), or a full-length peripheral surface (116) that extends between the first full-length-optical-core end face (112) and the second full-length-optical-core end face (114), at least a portion of the electromagnetic radiation (118) exits the full-length optical core (110) via the full-length peripheral surface (116) to irradiate, in an interior volume (182) 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 (180) of the feedstock line (100).