Cement Ink Shear Thinning for 3D Printing
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Solution Overview
Problem
Existing 3D printing technologies face challenges in producing complex architecture structures with desired geometries and mechanical properties due to issues like particle jamming and difficulty in extruding cement-based inks without high printing pressure, which limits the resolution and feasibility of printing complex structures.
Innovation Solution
A printable cement composition incorporating American Petroleum Institute (API) Class G cement, hydrophilic bentonite, polycarboxylate ether, hydroxyethyl cellulose, and 2-ethyl-1-hexanol, which provides shear thinning properties and rapid gel strength development, enabling extrusion through micronozzles at ambient conditions and maintaining filamentary shape, thus facilitating high-resolution 3D printing of complex structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cement is used as a 3D printing material at ambient conditions, then the material is readily available and cost-effective, but particle jamming and solidification occur over time making high-resolution printing impossible
Solution Approach 1:
The patent modifies the rheological parameters of cement by adding superplasticizers and viscosity modifiers. These additives change the flow behavior and setting characteristics of cement, enabling it to maintain printability at ambient conditions while achieving high-resolution printing. The chemical composition parameters are adjusted to prevent premature solidification.
Solution Approach 2:
The patent introduces intermediary substances (superplasticizers, viscosity modifiers, and other additives) that mediate between the cement particles and water. These intermediaries prevent particle jamming by dispersing cement particles uniformly and controlling the setting rate, thereby enabling high-resolution printing without requiring specialized expensive materials.
2Ease of operation
If high printing pressure is applied to extrude cement-based ink, then the material can be extruded through nozzles, but the process becomes complex and less feasible for practical applications
Solution Approach 1:
The patent changes the rheological parameters of the cement-based ink by incorporating superplasticizers and viscosity modifiers. These additives reduce the yield stress and improve flowability, allowing the ink to be extruded through nozzles at low printing pressures. The flow curve parameters are optimized to achieve easy extrusion without high pressure.
3Stability of the object's composition
If the extruded ink maintains filamentary shape with sufficient modulus and yield stress, then the printed structure remains stable without deformation, but the ink becomes difficult to extrude without high pressure
Solution Approach 1:
The patent creates a dynamic rheological profile where the ink exhibits shear-thinning behavior during extrusion (low viscosity under high shear stress) and rapid gel strength development after extrusion (high modulus and yield stress at rest). This dynamic transition allows easy extrusion followed by immediate shape stabilization without requiring continuously high pressure.
Solution Approach 2:
The patent incorporates additives that prepare the ink for rapid gel strength development after extrusion. The superplasticizers and viscosity modifiers are pre-mixed to ensure immediate structural reinforcement upon deposition, stabilizing the filamentary shape before any deformation can occur.
4Adaptability or versatility
If complex architecture structures with various geometric shapes are printed, then the functional performance is enhanced, but existing 3D printing materials and technologies cannot produce the desired geometries and mechanical properties
Solution Approach 1:
The patent creates a composite cement-based ink system combining cement, superplasticizers, viscosity modifiers, and other additives in specific proportions. This composite formulation provides the unique combination of extrudability, shape retention, and mechanical properties needed to print complex architecture structures with various geometric shapes and enhanced functional performance.
Solution Approach 2:
The patent optimizes multiple parameters including chemical composition, rheological properties, and setting characteristics to enable the printing of complex architectures. The water-cement ratio, additive concentrations, and curing conditions are adjusted to achieve both geometric precision and enhanced mechanical properties for functional structures.
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 cement ink allows for the extrusion of cement-based structures with improved mechanical properties, such as strength and toughness, enabling the printing of complex architectures without deformation and reducing manufacturing costs and effort, while minimizing issues related to workability and flowability.
Implementation Method 1
provides shear thinning properties and rapid gel strength development
Implementation Method 2
provides shear thinning properties and rapid gel strength development
Data Source
AI summary
Provide is a cement ink for a cement ink for 3D printing (which also includes additive manufacturing) of 3D cement structures and materials. The cement ink includes an American Petroleum Institute (API) Class G cement, a nano-clay, a superplasticizer, a hydroxyethyl cellulose, and a defoamer. The nano-clay may be hydrophilic bentonite. The superplasticizer may be a polycarboxylate ether. The defoamer may be 2-ethyl-1-hexanol. Processes for forming the cement ink and printing 3D cement structures using the cement ink are also provided.