Additive-Ablative 3D Fabrication for High-Resolution Open-Air Printing
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Solution Overview
Problem
Conventional solid free-form fabrication (SFF) techniques face challenges with oxygen inhibition during the curing process, particularly in low-intensity curing methods like UV LED or UVA cure, leading to incomplete curing and sticky surfaces, and struggle with achieving high resolution and speed.
Innovation Solution
The method combines additive manufacturing with selective ablation using a laser beam, allowing for resolutions as low as 1 μm and vertical resolutions of approximately 0.1 μm, enabling the use of various materials and embedding foreign elements within the fabrication process, while operating in an open space environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low-intensity UV LED or UVA curing is used, then energy consumption is reduced and material damage is minimized, but oxygen inhibition occurs leading to incomplete curing and sticky surfaces
Solution Approach 1:
A release layer is introduced as an intermediary between the oxygen-inhibited uncured layer and the cured layer. This release layer prevents oxygen from the atmosphere from reaching and inhibiting the curing process at the surface, while still allowing the underlying material to cure completely. The release layer acts as a barrier that mediates the interaction between oxygen and the photopolymerizable material.
Solution Approach 2:
The invention creates a localized inert environment by using the release layer to exclude atmospheric oxygen from the curing interface. This effectively simulates an oxygen-free environment at the curing surface, allowing complete polymerization to occur without oxygen inhibition, even when using low-intensity UV LED or UVA curing methods.
2Manufacturing precision
If conventional material dispensing is used, then material deposition is achieved, but resolution is limited and fabrication speed is slow
Solution Approach 1:
The invention replaces mechanical material dispensing systems with a light-based selective curing system. Instead of precisely controlling material deposition through mechanical means, the system dispenses a layer of photopolymerizable material and uses selective UV curing to define the desired geometry. This substitution of mechanical dispensing with optical processing enables both higher resolution and faster fabrication speeds.
Solution Approach 2:
The invention changes the fundamental parameter of material deposition from controlled dispensing to controlled curing. By maintaining a consistent material layer thickness and using variable UV curing patterns, the system achieves high resolution through optical parameter control rather than mechanical dispensing precision, thereby improving both resolution and fabrication speed.
3Manufacturing precision
If selective ablation is used, then high resolution is achieved, but material removal requires precise energy control
Solution Approach 1:
Instead of using ablation to remove material and define geometry, the invention inverts the approach by depositing material and using selective curing to define geometry through polymerization. This inversion replaces energy-intensive ablation with lower-energy photopolymerization, achieving the same geometric definition purpose with better energy efficiency and less stringent energy control requirements.
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
This approach provides improved resolution and fabrication speed, allows for the use of diverse materials, and enables the embedding of electronic devices within the fabricated objects, overcoming the limitations of oxygen inhibition and achieving high-quality, precise 3D object creation.
Implementation Method 1
selective ablation using a laser beam
Implementation Method 2
selective ablation of the support material
Implementation Method 3
The UV laser causes the bath to polymerize where the laser beam strikes the surface of the bath
Data Source
AI summary
A method of solid free-form fabrication (SFF) includes receiving SFF data collectively pertaining to a three-dimensional shape of the object and comprising a plurality of slice data each defining a layer of the object. The method further includes dispensing a building material containing a solvent, drying the building material so as to remove at least some of the solvent from the building material and leveling the building material. The method further includes selectively ablating the building material, for at least several of the multiple layers, according to the slice data corresponding to the layer, and dispensing at least one additional building material onto the building material to fill vacant regions formed in the multiple layers by the selective ablation. A resolution of the dispensing of the additional building material may be less than a resolution of the selective ablation.