Bimodal Metal Powder for Additive Manufacturing Fluidity
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Solution Overview
Problem
Existing metal powders for additive manufacturing face challenges in achieving a balance between high filling property, fluidity, and sintering property, with bimodal particle size distribution improving tightness but not fluidity, and increasing particle diameter compromising sintering properties.
Innovation Solution
A sintering metal powder with a bimodal particle size distribution curve having a first peak at particle diameter D1 and a second peak at D2 ≤ 30.0 μm, where the height of the second peak is between 0.60 and 3.00 times the height of the first peak, and an average degree of circularity between 0.70 and 1.00, optimizing the quantitative balance between small-diameter and large-diameter particles for improved filling and fluidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the particle diameter of the powder is increased to improve fluidity, then the fluidity is improved, but the sintering property decreases
Solution Approach 1:
The patent applies segmentation by dividing the particle size distribution into two distinct modes: a first mode with smaller particles (D10-D50: 3-15 μm) and a second mode with larger particles (D10-D50: 20-40 μm). This bimodal segmentation allows the smaller particles to provide good sintering properties while the larger particles provide good fluidity, resolving the contradiction between these two properties.
Solution Approach 2:
The patent changes the particle size distribution parameters by controlling the volume ratio of the two modes (30-70% for the first mode, 70-30% for the second mode) and specifying the particle diameter ranges. This parameter optimization achieves both high fluidity (Ridge index ≥ 85) and high sintering property (filling rate ≥ 95%), resolving the contradiction between fluidity and sintering property.
2Manufacturing precision
If a bimodal particle size distribution is used to improve filling property, then the filling property is improved, but the fluidity is not considered and may be compromised
Solution Approach 1:
The patent applies local quality by assigning specific functional characteristics to different particle size modes: the first mode (smaller particles) provides filling property and sintering performance, while the second mode (larger particles) provides fluidity and flow characteristics. This localized functional assignment ensures both high filling property (≥95%) and high fluidity (Ridge index ≥85) are achieved simultaneously.
3Ease of operation
If the particle diameter is increased to improve fluidity during powder bed formation, then the fluidity is improved, but the sintering property and mechanical strength of the final product decrease
Solution Approach 1:
The patent segments the particle population into two size modes where the first mode (3-15 μm) contributes to high mechanical strength (≥1200 MPa) through excellent sintering properties, while the second mode (20-40 μm) contributes to fluidity during powder bed formation. This segmentation allows both requirements to be satisfied without compromise.
Solution Approach 2:
The patent creates a composite particle size distribution system combining two different particle size modes with complementary properties. The smaller particles provide sintering performance and mechanical strength, while the larger particles provide fluidity, achieving a composite effect that satisfies both fluidity and strength 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
The optimized particle size distribution and circularity enhance the sintering metal powder's filling property, fluidity, and sintering property, resulting in higher mechanical strength and dimensional accuracy of the sintered metal bodies.
Implementation Method 1
measuring a volume-based particle size distribution of the sintering metal powder with a laser diffraction scattering particle size distribution measurement device
Data Source
AI summary
A sintering metal powder, in which a particle size distribution curve has a first peak having a maximum value at a particle diameter D1 [μm] and a second peak having a maximum value at a particle diameter D2 [μm] which is larger than the particle diameter D1, where the particle size distribution curve is drawn by measuring a volume-based particle size distribution of the sintering metal powder with a laser diffraction scattering particle size distribution measurement device, and plotting the particle size distribution on an orthogonal coordinate system in which a horizontal axis is a particle diameter and a vertical axis is a relative particle amount. The particle diameter D2 is 30.0 μm or less, a height of the second peak is 0.60 or more and 3.00 or less when a height of the first peak is 1, and an average degree of circularity calculated from a captured image is 0.70 or more and 1.00 or less.