NMR-Guided Ceramic Colloidal Stability for Extrusion Printing

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Solution Overview

Problem

Achieving consistent ceramic suspension stability in extrusion-based additive manufacturing is challenging due to variations in feedstock powder and processing, leading to issues like sedimentation and inconsistent rheology, which are difficult to predict and optimize using existing experimental methods.

Innovation Solution

Predicting ceramic colloidal suspension stability by measuring spin-lattice T1 relaxation times using nuclear magnetic resonance (NMR) to determine Hansen Solubility Parameters (HSP) for solvent and additive selection, enabling rapid identification of suitable dispersants and solvents that enhance suspension stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If extensive testing and screening of powders, mediums, dispersants, and additives is performed to find ideal formulation, then ceramic suspension stability and consistency are improved, but time consumption and complexity increase significantly

Engineering Contradiction:

Improveceramic suspension stabilityVSAvoidtesting and screening time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by measuring T1 relaxation times of ceramic powders in different solvents before formulating the final suspension. This preliminary measurement allows prediction of which solvent-ceramic combinations will yield stable suspensions, eliminating the need for extensive subsequent testing and screening of dispersants and additives.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/experimental testing system with a nuclear magnetic resonance (NMR) based measurement system. Instead of physically testing numerous formulations to assess stability, the T1 relaxation time measurement provides predictive information about suspension stability, substituting complex experimental screening with a streamlined analytical method.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional experimental methods are used to optimize ceramic suspension formulations, then comprehensive material characterization is achieved, but the process becomes complex and time-consuming

Engineering Contradiction:

Improvematerial characterization accuracyVSAvoidtesting process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the critical predictive information (T1 relaxation time) from the complex NMR measurement process and uses it as a standalone indicator for suspension stability. By focusing on this single extracted parameter, the method achieves accurate material characterization without requiring the full complexity of traditional multi-parameter experimental optimization.

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If variations in feedstock powder and processing parameters are accommodated through extensive formulation screening, then consistent rheology is achieved, but productivity decreases due to repeated testing

Engineering Contradiction:

Improverheology consistencyVSAvoidformulation development rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary T1 relaxation time measurements to predict which ceramic-solvent combinations will yield consistent rheology. This preliminary assessment allows formulators to select optimal combinations before processing, avoiding the need for repeated testing and screening that would otherwise be required to achieve rheology consistency, thereby improving productivity.

Inventive Principle:

Principle #10Preliminary action

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 method allows for rapid and accurate prediction of ceramic suspension stability, reducing the need for extensive testing and ensuring consistent rheology and density in additively manufactured structures.

Implementation Method 1

measuring spin lattice T1 relaxation times by nuclear magnetic resonance

Methodology Applied

Scientific EffectNuclear magnetic resonance:

Implementation Method 2

measuring spin lattice T1 relaxation times

Methodology Applied

Scientific EffectSpin-lattice relaxation: Stress Relaxation

Data Source

PatentUS12405237B2Predicting ceramic colloidal suspension stability for extrusion-based additive manufacturing

Publication Date: 2025.09.02 JOHNS HOPKINS UNIVERSITY

AI summary

A process for selecting an additive and/or solvent for a colloidal ceramic suspension includes measuring spin lattice T1 relaxation times by nuclear magnetic resonance for a ceramic-solvent pair and an additive-solvent pair, wherein the solvent is selected from a plurality of different solvents, and wherein the additive is selected from a plurality of different additives. The process includes determining a relaxation number for each of the ceramic-solvent pairs and the additive-solvent pairs from the spin lattice T1 relaxation times, wherein a higher relaxation number is indicative of strong affinity between the additive and solvent and between the ceramic and solvent. Additionally, the process includes selecting the additive and the solvent based on the relaxation number having the highest relaxation number for the colloidal ceramic suspension.