Continuous Ceramic Additive Manufacturing for Dense 3D Parts
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Solution Overview
Problem
Conventional ceramic processing methods struggle to produce high-density, complex three-dimensional ceramic objects without significant porosity or optical artifacts, especially when using additive manufacturing technologies like stereolithography, due to low powder bed packing density and challenges in processing multi-component materials.
Innovation Solution
A continuous additive manufacturing method involving a photopolymerizable slurry or sol with ceramic particles, where the slurry is selectively polymerized and solvent is extracted to form an aerogel or xerogel, followed by heat treatment and sintering, resulting in a ceramic article with a density of 94% or greater and minimal optical artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional stereolithography is used to process ceramic-filled photopolymers, then three-dimensional architecture can be formed, but the green body density remains low resulting in porous final ceramic articles
Solution Approach 1:
The patent changes the physical-chemical parameters of the slurry system by using a photopolymerizable slurry with ceramic particles suspended in a liquid medium that undergoes photopolymerization. This transforms the material state from a simple powder bed to a gel-like structure that maintains high particle packing density while enabling complex 3D geometry formation through selective curing.
Solution Approach 2:
The patent employs a composite photopolymerizable slurry system combining ceramic particles with a photopolymerizable liquid medium containing photoinitiators and monomers/oligomers. This composite approach allows the liquid matrix to fill interstices between ceramic particles, achieving high green density while the photopolymerization process binds particles together to form dense, low-porosity ceramic articles after solvent removal and sintering.
2Shape
If layer-by-layer additive manufacturing is used, then complex three-dimensional shapes can be produced, but production rate is slow and material uniformity is compromised
Solution Approach 1:
The patent implements continuous additive manufacturing where the build substrate moves continuously through the photopolymerizable slurry bath while actinic radiation selectively cures material. This eliminates the stop-start nature of conventional layer-by-layer processing, maintaining continuous material deposition and curing action, thereby significantly increasing production rate while preserving the ability to form complex 3D shapes through programmed substrate motion and selective irradiation.
3Manufacturing precision
If high ceramic particle loading is used in photopolymerizable slurry, then high-density ceramic articles can be obtained, but optical properties deteriorate due to increased opacity and scattering
Solution Approach 1:
The patent optimizes the particle size distribution parameter, using predominantly sub-visual particles (average diameter 0.1-10 micrometers, preferably 0.5-5 micrometers) that scatter less visible light. This parameter change allows high ceramic loading (5-50 wt%) to achieve high green density and final ceramic density while minimizing optical scattering and maintaining adequate transparency for photopolymerization and final optical properties.
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 method achieves high-density ceramic articles with reduced optical artifacts and uniform material distribution, overcoming the limitations of traditional layer-by-layer methods by ensuring faster production rates and improved material consistency.
Implementation Method 1
selectively polymerizing the photopolymerizable slurry or sol using actinic radiation
Implementation Method 2
heat treating the aerogel article or the xerogel article to form a porous ceramic article
Implementation Method 3
sintering the porous ceramic article to form a sintered ceramic article
Data Source
AI summary
The present disclosure provides a method of making a ceramic article. The method includes (a) obtaining a photopolymerizable slurry or sol including a plurality of ceramic particles distributed in the photopolymerizable slurry or sol and (b) selectively polymerizing the photopolymerizable slurry or sol using actinic radiation and continuous movement of a build substrate through the photopolymerizable slurry or sol to form a gelled article. The method also includes (c) extracting solvent from the gelled article to form an aerogel article or a xerogel article; (d) heat treating the aerogel article or the xerogel article to form a porous ceramic article; and (e) sintering the porous ceramic article to form a sintered ceramic article. The sintered ceramic article exhibits a particular density. Further, additive manufactured ceramic articles are provided that exhibit a particular density, opacity, or both. Preferably, all cross-sectional portions of an interior of the ceramic article having selected dimensions are free of a frequency analysis signal maxima larger than a background signal.