Additive Manufacturing Powder Mixture Flowability
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Solution Overview
Problem
Powders with low sphericity in additive manufacturing exhibit inadequate flowability, which affects the efficiency of forming multi-layer shaped objects, particularly in methods like selective beam melting and fused deposition modeling.
Innovation Solution
A mixture of a first metal powder with low sphericity and a second powder with higher sphericity, where the second powder has an average diameter one-tenth that of the first powder, is used to improve flowability. The first powder is the primary component, occupying 99% or more of the volume, while the second powder, with a sphericity of 0.8 or higher, is added at a volume fraction of 0.001% to 1%, enhancing the flowability by reducing friction and facilitating smoother spreading and melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If powder with low sphericity is used, then production cost is reduced, but flowability deteriorates
Solution Approach 1:
A flowability improvement agent is introduced as an intermediary substance between the low sphericity powder particles. This agent coats or interacts with the particle surfaces to reduce inter-particle friction and improve flow characteristics, allowing the use of cost-effective low sphericity powder while achieving adequate flowability for additive manufacturing processes
Solution Approach 2:
The invention changes the surface parameters of the powder particles by applying a flowability improvement agent. This modifies the friction coefficient and surface properties of the particles, transforming them from having poor flowability to having sufficient flowability for layer-by-layer spreading in additive manufacturing
2Ease of manufacture
If powder with low sphericity is used, then manufacturing cost is reduced, but modeling accuracy deteriorates
Solution Approach 1:
The flowability improvement agent acts as a mediator that enables low sphericity powder to achieve uniform layer spreading and consistent packing density. This uniformity is critical for modeling accuracy, ensuring that each layer is deposited evenly without variations that would compromise the precision of the final 3D printed object
Solution Approach 2:
By modifying the surface parameters of low sphericity particles through the flowability improvement agent, the invention achieves consistent particle behavior during layer deposition. This leads to uniform packing density and layer thickness, which are essential for maintaining high modeling accuracy while using cost-effective powder
3Quantity of substance
If powder with low sphericity is used, then material cost is reduced, but layer uniformity deteriorates
Solution Approach 1:
The flowability improvement agent serves as a uniform coating or surface modifier that standardizes the interaction between low sphericity particles and the build platform. This ensures consistent layer formation and uniform composition throughout the printed object, overcoming the inherent variability caused by particle shape irregularities
Solution Approach 2:
The invention applies a treatment that changes the surface parameters of the powder particles, creating a uniform interface between particles and between particles and the build platform. This parameter modification ensures consistent packing behavior and layer uniformity, maintaining stable composition throughout the object despite using low sphericity powder
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 improved flowability of the powder mixture allows for better spreading and melting, resulting in enhanced modeling accuracy, reduced void ratios, and increased strength of the multi-layer structures, suitable for various applications such as mechanical parts and medical implants.
Implementation Method 1
The second powder, with a sphericity of 0.8 or higher, is added at a volume fraction of 0.001% to 1%, enhancing the flowability by reducing friction
Implementation Method 2
a selective beam melting method in which a powder previously spread in a layer (powder bed) is locally melted by a heat source such as a laser or electron beam
Data Source
Figure 1~2
Figure 3(a)~3(g)
AI summary
Provided is a powder that has improved flowability even when the powder contains a powder having low sphericity. This is achieved by the following means. A powder for additive manufacturing for use in producing a multi-layer shaped object by repeatedly forming a solidified layer by melting a powder spread in a layer by beam irradiation, comprising: a first metal powder having an average diameter of 10 µm or more but 200 µm or less; and a second powder whose sphericity is higher than that of the first metal powder and whose average diameter is 1/10 or less of that of the first metal powder, wherein a volume fraction of the first metal powder is 99% or more and a volume fraction of the second powder is less than 1%.