Selective Deposition and Fusion Additive Manufacturing with Reduced Binder
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Solution Overview
Problem
Current additive manufacturing methods, such as powder bed fusion and directed energy deposition, face challenges including high capital costs, safety hazards, complexity leading to defects, variability, anisotropic microstructures, and limitations in producing large-sized components with high density and geometrical accuracy, particularly due to high binder content and long post-processing times.
Innovation Solution
The Selective Deposition and Fusion Additive Manufacturing (SDFAM) method uses a metal alloy paste with minimal binder content, a synchronized two-step extrusion mechanism, and multi-objective optimization of printing parameters to achieve high-density, defect-free metallic parts with reduced post-processing time, integrating direct ink writing and thermal energy application for layer-by-layer fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If powder bed fusion or directed energy deposition is used to produce fully dense parts, then manufacturing precision and strength are improved, but device complexity and capital costs increase
Solution Approach 1:
The patent replaces complex mechanical powder handling systems with a simpler paste-based extrusion approach. Instead of using powder bed fusion or directed energy deposition with complex powder spreading and melting systems, the invention uses a paste that is extruded layer-by-layer, eliminating the need for complex powder bed mechanisms while achieving similar dense part production.
Solution Approach 2:
The patent changes the fundamental material parameter from metallic powder to metallic paste. This parameter change simplifies the manufacturing process by eliminating powder handling complexities while maintaining the ability to produce dense parts. The paste formulation with specific binder content and particle size distribution enables simplified processing without sacrificing part density.
2Volume of moving object
If conventional AM methods are used to produce large-sized components, then part size is improved, but manufacturing precision and density decrease
Solution Approach 1:
The patent segments the manufacturing process into sequential layer deposition steps. By building components layer-by-layer through extrusion of metallic paste, the method maintains precision for large-sized components. Each layer is deposited with controlled thickness and composition, allowing cumulative construction of large parts while maintaining geometrical accuracy through process control at each stage.
3Ease of manufacture
If high binder content is used in paste formulations, then ease of manufacture is improved, but productivity and post-processing time increase
Solution Approach 1:
The patent optimizes the binder content parameter in the paste formulation to a specific range (5-20 wt%). This parameter change balances manufacturability with productivity. The optimized binder content provides sufficient paste processability for extrusion while minimizing post-processing time. The patent also optimizes particle size distribution (D10-D90 ratio of 0.05-0.5) to enhance paste flowability and reduce processing 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
SDFAM achieves over 95% dense metallic parts with minimal macroporosity and warping in just 22 hours of thermal post-processing, overcoming the limitations of existing methods by improving feedstock efficiency, geometrical fidelity, and reducing post-processing time.
Implementation Method 1
The SDFAM method also includes applying thermal energy to the patterned layer of metallic powder to fuse the patterned layer of metallic powder into a patterned layer of solid metallic build material
Implementation Method 2
This is achieved by employing a focused thermal energy source (e.g., laser or electron beam) to selectively fuse raw metallic feedstock, in the form of powder or wire, via full melting
Implementation Method 3
The removing of the solvent and the binder may comprise heating the metallic paste to a first temperature
Implementation Method 4
The removing of the solvent and the binder may comprise heating the metallic paste to a first temperature
Data Source
AI summary
A SDFAM method includes forming a patterned layer of metallic paste on a build structure. The metallic paste has a solvent and a binder. The method also includes removing the solvent and the binder from the metallic paste to generate a patterned layer of metallic powder. The SDFAM method also includes applying thermal energy to the patterned layer of metallic powder to fuse the patterned layer of metallic powder into a patterned layer of solid metallic build material, and repeating the forming, the removing, and the applying to form a plurality of patterned layers of solid metallic build material to create an object.