Metal Powder Production via Mechanical Comminution
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Solution Overview
Problem
Current methods for producing metal powders for additive manufacturing are energy-intensive and costly, particularly for ductile materials like copper and aluminum, and often require phase transformation, which is not suitable for all materials, and there is a need for cost-effective and sustainable alternatives that maintain ductile properties.
Innovation Solution
A mechanical processing method involving comminution and classification to produce metal powders with a particle size range of 10 µm to 300 µm from metal chips or foils, using shear stress and impact stress without phase transformation, ensuring spherical particle shape and size distribution suitable for additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional metallurgical processes with phase transformation are used to produce metal powders, then the powders achieve suitable particle size and shape for additive manufacturing, but the production costs and energy consumption increase significantly
Solution Approach 1:
The patent replaces thermal and chemical processes (metallurgical phase transformation) with purely mechanical comminution processes. Mechanical energy in the form of impact stress and shear stress is used to reduce metal chips and foils to powder form, eliminating the need for energy-intensive melting, atomization, and phase transformation steps while achieving the required particle size distribution and spherical shape
Solution Approach 2:
The patent changes the fundamental processing parameters from thermal/chemical domain to mechanical domain. By controlling mechanical stress parameters (impact velocity, shear stress intensity) and process conditions (atmosphere, temperature maintenance), the method achieves powder production with comparable or superior particle characteristics to traditional methods but with significantly reduced energy consumption
2Use of energy by moving object
If mechanical comminution processes are used for ductile metals, then energy consumption is reduced, but the ductile material properties make comminution difficult and particle shape control challenging
Solution Approach 1:
The patent employs periodic impact loading where metal chips and foils are repeatedly subjected to high-velocity impact stress from falling onto a grate. This periodic action, combined with intermittent shear stress application, progressively breaks down ductile materials by creating and propagating micro-cracks over multiple cycles, eventually fragmenting them into fine powder particles with controlled morphology
Solution Approach 2:
The patent applies preliminary mechanical actions to ductile metals by first subjecting them to impact stress to create initial fractures and reduce size, then applying shear stress to further comminute the material. This staged preliminary mechanical treatment prepares the ductile material for final size reduction and spherical shape formation without requiring phase transformation
3Manufacturing precision
If phase transformation processes are used to produce metal powders, then chemical composition can be precisely adjusted, but the process complexity and cost increase
Solution Approach 1:
The patent extracts the essential function of metal powder production from complex metallurgical processes and isolates it to pure mechanical comminution. By taking out the phase transformation step and replacing it with mechanical impact and shear stress, the method maintains the ability to produce powders with controlled particle size and shape while eliminating the complex thermal and chemical process steps required for composition adjustment
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
This method reduces production costs by up to a factor of 10 compared to traditional metallurgical processes, enabling the production of high-quality metal powders with precise particle size distribution and shape, suitable for additive manufacturing and coating applications, while maintaining ductile properties without thermal influence.
Implementation Method 1
comminution and classification to produce metal powders with a particle size range of 10 µm to 300 µm from metal chips or foils, using shear stress and impact stress
Implementation Method 2
comminution and classification to produce metal powders with a particle size range of 10 µm to 300 µm from metal chips or foils, using shear stress and impact stress
Data Source
AI summary
In the process, in a first step (i), chips with a maximum wall thickness of 500 µm or metal foil with a maximum wall thickness of 300 µm, consisting of the respective metal or a metal alloy, are freed from organic components adhering to their surfaces. In a second step (ii), a purely mechanical pre-shredding process is carried out using rotating tools under shear stress, yielding particles with a maximum particle size of 20,000 µm. In a subsequent third step (ii), a further shredding process is carried out using impact stress to further reduce the size and round the particles. In a fourth step (iv), at least one-stage classification is performed, in which particles with a particle size > 300 µm are separated and particles with a particle size < 300 µm are used.