Meaning
The mass flow relationship between the atomizing gas and the liquid metal stream determines the final size distribution of metal powder particles. A higher atomization gas-to-melt ratio increases the kinetic energy transferred to the molten metal stream. This energy transfer breaks the liquid stream into finer droplets.
Process Impact
Increasing the ratio of gas to melt increases the proportion of fine particles in the powder batch. This change happens because more kinetic energy is available per unit mass of molten metal to overcome the surface tension of the liquid stream. The distribution curve shifts toward smaller diameters as a result.
Consequently, the yield of powder suitable for additive manufacturing is maximized when this parameter is carefully controlled.
Control Method
Mass flow controllers regulate the gas input while the nozzle diameter and melt temperature determine the metal flow rate. Flow rates are adjusted dynamically during the run to maintain a stable ratio. Transducers track both parameters continuously.
Production Tradeoff
High ratios yield powder that is highly suitable for powder bed fusion but also increase gas consumption costs. Extremely low ratios lead to coarse powders that require secondary milling. Operators must choose the setting that balances powder yield with gas expenses.
