Metal Oxide Paste Extrusion for Additive Manufacturing
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Solution Overview
Problem
Current additive manufacturing technologies are limited in producing three-dimensional objects composed of high melting materials like metals and metal/ceramic composites due to restrictions on compatible materials and the need for expensive laser and electron beam systems in high vacuum environments, preventing the use of various material systems.
Innovation Solution
A method involving the extrusion of metal oxide pastes comprising metal oxide particles, a polymeric binder, and an organic solvent to form three-dimensional metal oxide objects, which are then reduced and sintered using a reducing gas to produce dense metallic objects, allowing for the creation of complex metal, alloy, or ceramic composite structures with controlled porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser and electron beam systems are used in high vacuum environments for additive manufacturing, then metal oxidation is prevented, but equipment cost and system complexity increase significantly
Solution Approach 1:
The patent uses a binder jetting intermediary approach where a binding material is deposited onto metal powder layers, and the entire structure is subsequently sintered in a controlled atmosphere. This intermediary binding step allows the use of simpler, lower-cost equipment compared to direct laser or electron beam systems, while still achieving oxidation prevention through the sintering atmosphere control.
Solution Approach 2:
The patent employs an inert or controlled atmosphere (such as nitrogen or vacuum) during the sintering process to prevent metal oxidation. This approach achieves the same oxidation protection as laser/electron beam methods but using a simpler thermal field application without requiring complex high-power beam systems.
2Temperature
If laser and electron beam systems are used for additive manufacturing, then high melting materials can be processed, but production cost increases
Solution Approach 1:
The binder serves as an intermediary that holds the metal powder structure together during handling and allows subsequent sintering at lower temperatures than direct melting approaches. This intermediary binding enables the use of simpler furnaces rather than expensive laser or electron beam systems, reducing production cost while still achieving high melting material processing.
Solution Approach 2:
The binder is applied in advance to the metal powder layers before sintering, creating a green body structure that maintains shape during handling. This preliminary action allows the subsequent sintering process to occur at lower temperatures and simpler equipment, reducing overall production cost compared to direct high-energy beam processing.
3Adaptability or versatility
If metal powders with particles greater than 1 μm are used, then material selection is limited, but manufacturing cost decreases
Solution Approach 1:
The patent changes the particle size parameter to use finer metal powders (less than 1 μm) that were previously considered too fine for conventional additive manufacturing. The binder jetting and sintering process enables effective use of these fine particles, expanding material versatility while maintaining cost-effectiveness through the simplified equipment approach.
Solution Approach 2:
The binder provides localized adhesion to metal powder particles, enabling the effective use of fine particles that would otherwise be difficult to handle and process. This local binding quality allows the process to accommodate a broader range of material sizes and types, increasing adaptability without proportionally increasing cost.
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
Enables the efficient production of three-dimensional metallic objects with fine surface finish and controlled porosity, expanding the range of usable materials beyond traditional limits and enabling applications in diverse technologies such as energy, biomedical, and advanced manufacturing.
Implementation Method 1
exposing the three-dimensional metal oxide object to a reducing gas at a temperature and for a period of time sufficient to reduce and to sinter the metal oxide particles
Implementation Method 2
exposing the three-dimensional metal oxide object to a reducing gas at a temperature and for a period of time sufficient to reduce and to sinter the metal oxide particles
Data Source
AI summary
Methods of forming three-dimensional metallic objects are provided. A metal oxide paste comprising metal oxide particles, a polymeric binder and an organic solvent is extruded through a tip to deposit sequential layers of the metal oxide paste on a substrate to form a three-dimensional metal oxide object. The three-dimensional metal oxide object is exposed to a reducing gas at a temperature and for a period of time sufficient to reduce and to sinter the metal oxide particles to form a three-dimensional metallic object. Depending upon the composition of the metal oxide paste, the three-dimensional metallic object may be composed of a single metal, a simple or complex metal-metal alloy, or a metal-ceramic composite.