Optical Modifiers in Additive Manufacturing Feedstock
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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 of the resin, leading to incomplete or uneven curing due to shadowing effects.
Innovation Solution
Incorporating optical modifiers within the feedstock line, such as full-length or partial-length optical waveguides, which redirect electromagnetic radiation to penetrate the resin even in shadowed regions, ensuring thorough and even curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reinforcing fibers are added to the feedstock material, then the mechanical strength of the manufactured part is improved, but the curing completeness of the resin deteriorates due to shadowing effects
Solution Approach 1:
The patent introduces optical modifiers as intermediary elements within the feedstock material. These modifiers have high refractive indices and are positioned between the curing energy source and the resin, specifically in regions where direct line-of-sight curing is blocked by opaque fibers. The optical modifiers redirect and scatter electromagnetic radiation, acting as mediators that deliver curing energy to shadowed regions without being present in the final cured part.
2Productivity
If direct electromagnetic radiation is used for curing, then the curing speed is improved, but the uniformity of curing deteriorates in shadowed regions
Solution Approach 1:
The patent addresses the limitation of direct line-of-sight curing by introducing optical modifiers that operate in a different dimensional approach. Instead of relying solely on direct radial propagation of electromagnetic radiation, the modifiers scatter and redirect energy in multiple directions, effectively adding angular and spatial dimensions to the curing process. This enables curing energy to reach shadowed regions through indirect paths.
Solution Approach 2:
The patent utilizes optical modifiers with specifically selected high refractive indices to change the optical parameters of the feedstock material. By incorporating materials with refractive indices significantly higher than the resin (e.g., metal oxides, metal fluorides), the system alters the propagation characteristics of electromagnetic radiation, enabling enhanced scattering and redirection of curing energy into shadowed regions while maintaining overall curing speed.
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
Facilitates more efficient, uniform, and complete curing of the resin within the feedstock line, improving the manufacturing process by ensuring that the resin is adequately cured despite being shielded from direct curing energy.
Implementation Method 1
at least the one optical modifier causes the electromagnetic radiation to irradiate, in the interior volume of the feedstock line, the resin that, due at least in part to the elongate filaments, is not directly accessible to the electromagnetic radiation
Implementation Method 2
at least the one optical modifier causes the electromagnetic radiation to irradiate
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 to solidify the feedstock material
Data Source
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AI summary
A system (700) for additively manufacturing an object (136) comprises feedstock-line supply (702), delivery guide (704), and curing mechanism (706). The feedstock-line supply (702) dispenses a feedstock line (100) that comprises elongate fibers (104), a resin (124) that covers the elongate fibers (104), and at least one optical modifier (123) that is interspersed among the elongate filaments (104). The delivery guide (704) is movable relative to a surface (708), receives the feedstock line (100), and deposits it along a print path (705). The curing mechanism (706) is directs electromagnetic radiation (118) at the exterior surface (180) of the feedstock line (100) after it is deposited along the print path (705). When the electromagnetic radiation (118) strikes the outer surface (184) of at least one optical modifier (123), the optical modifier (123) causes the electromagnetic radiation (118) to irradiate, in the 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).