Nano-Sized Ceramic Sol Additive Manufacturing for Dental Articles
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Solution Overview
Problem
Existing additive manufacturing processes for ceramics face challenges in achieving high density, strength, accuracy, and translucency, particularly in producing dental and orthodontic articles, due to limitations in particle size and rheological properties of ceramic slurries, which result in low theoretical density and mechanical performance.
Innovation Solution
A process involving a printing sol with nano-sized particles, a solvent, and a radiation-curable component, processed to form a gel state article that undergoes significant volume shrinkage during heat treatment, achieving densities above 98.5% of theoretical density, translucency greater than 30%, and biaxial flexural strength of at least 450 MPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high particle load is used in the slurry to obtain high green density, then the density and mechanical strength of the ceramic article are improved, but the rheological properties deteriorate making the slurry difficult to process in additive manufacturing
Solution Approach 1:
The patent changes the particle size parameter from conventional micrometer-scale to nanometer-scale (1-100 nm). This parameter change allows achieving high particle load (60-80 wt%) while maintaining favorable rheological properties with viscosity below 500 mPa·s, resolving the contradiction between green density and processability
Solution Approach 2:
The patent applies surface modification to the ceramic particles, creating different properties at the particle surface versus the bulk material. The surface-modified particles exhibit improved dispersion and rheological behavior while maintaining high density, allowing both high green density and good processability
2Ease of manufacture
If the particle load in the slurry is reduced to improve rheological properties, then the slurry becomes easier to process, but the green density decreases resulting in articles that cannot be sintered to full density without cracks
Solution Approach 1:
By changing the particle size to nanometer scale (1-100 nm), the patent achieves high particle concentration (60-80 wt%) while maintaining low viscosity (<500 mPa·s). This resolves the contradiction by allowing high green density without sacrificing rheological properties
Solution Approach 2:
The patent creates a composite slurry system combining nanometer-scale ceramic particles with a carefully selected binder system. This composite approach enables high particle loading while maintaining processability through the binder's rheological control
3Ease of manufacture
If conventional micrometer-scale particles are used, then the slurry has acceptable viscosity, but the resulting ceramic articles have low theoretical density and poor mechanical performance
Solution Approach 1:
The patent changes the particle size parameter from micrometers to nanometers (1-100 nm). This enables achieving both acceptable viscosity (<500 mPa·s) and high theoretical density (>98.5% after sintering), simultaneously improving manufacturability and mechanical performance
Solution Approach 2:
The patent segments the ceramic material into nanometer-scale primary particles. These ultra-fine particles can pack more densely and uniformly, achieving high theoretical density while the small size maintains favorable flow and viscosity characteristics
4Manufacturing precision
If high particle load is used to achieve high density, then the ceramic article achieves full density after sintering, but the intermediate body is not self-supporting during the additive manufacturing process
Solution Approach 1:
The patent uses nanometer-scale particles (1-100 nm) with high surface area to volume ratio. This enables forming self-supporting green bodies at high particle loading (60-80 wt%) while achieving >98.5% theoretical density after sintering, resolving both density and stability 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
The process enables the production of ceramic articles with high surface quality, accuracy, and mechanical strength, suitable for dental and orthodontic applications, while reducing material usage and processing time, and allowing for precise finishing of functional surfaces.
Implementation Method 1
a printing sol comprising nano-sized particles, a solvent, and a radiation-curable component... processed to form a gel state article
Implementation Method 2
Volume A of the 3-dim article in a gel state being more than 500% of Volume F of the ceramic article in its sintered state
Data Source
Figure 1A~1C
Figure 1D~2
Figure 3
AI summary
The present invention relates to a process for producing a ceramic article, the process comprising the steps of providing a printing sol, the printing sol comprising solvent, nano-sized particles, radiation curable monomer(s) and photoinitiator, the printing sol having a viscosity of less than 500 mPa*s at 23°C, processing the printing sol as construction material in an additive manufacturing process to obtain a 3-dim article being in a gel state, the 3-dim article having a Volume A, transferring the 3-dim article being in a gel state to a 3-dim article being in an aerogel state, heat treating the 3-dim article to obtain a sintered 3-dim ceramic article, the ceramic article having a Volume F, Volume A of the 3-dim article in a gel state being more than 500% of Volume F of the ceramic article in its sintered state. The invention also relates to a ceramic article obtainable according to such a process. The ceramic article can have the shape of a dental or orthodontic article.