ALM

Characterizing the particle size and shape of metal powders used in additive layer manufacturing (ALM) is crucial for achieving precise and consistent printing results. Here are some common methods used for this characterization:

Laser Diffraction: Laser diffraction is a widely used technique to measure the particle size distribution of metal powders. It involves passing a laser beam through a dispersed powder sample and analyzing the diffraction pattern to determine the particle size distribution. This method provides information on the range of particle sizes present in the powder.

Scanning Electron Microscopy (SEM): SEM allows for high-resolution imaging of metal powder particles. By visualizing the particles at a micro or nanoscale, SEM provides detailed information about particle morphology (shape and surface characteristics) and size. Quantitative analysis can be conducted to measure individual particle sizes and determine their shapes accurately.

Transmission Electron Microscopy (TEM): TEM provides even higher resolution than SEM and is used for studying metal powder particles at the nanoscale. It offers detailed images of individual particles, allowing precise measurements of particle size and shape characteristics.

Dynamic Light Scattering (DLS): DLS measures the hydrodynamic size of particles suspended in a liquid medium. It is suitable for analyzing smaller particles and nanoparticles in metal powder slurries, providing information about the size distribution and aggregation behavior.

Image Analysis: Digital image analysis involves capturing images of metal powder particles using optical microscopy or specialized imaging systems. Software analysis of these images can provide valuable data on particle size distribution, shape descriptors (such as aspect ratio, circularity, etc.), and particle packing density.

Surface Area Measurement: Techniques such as BET (Brunauer-Emmett-Teller) analysis are used to measure the specific surface area of metal powders. This measurement can indirectly infer particle size distribution and particle shape based on the surface area-to-volume ratio.

X-ray Powder Diffraction (XRD): XRD is used to study the crystallographic structure and phase composition of metal powders. While not directly measuring particle size and shape, it provides information about the crystalline structure, which can indirectly influence particle characteristics.

By combining multiple characterization techniques, including particle size distribution measurements and shape analysis, engineers and researchers can gain comprehensive insights into the properties of metal powders intended for additive layer manufacturing. This understanding is vital for optimizing printing parameters, ensuring powder flowability, controlling layer deposition, and achieving desired mechanical properties in printed parts.