Inert Gas Atomization Dynamics in Powder Production
Supersonic gas jets destabilize liquid metal streams through high-shear wave growth, where tight gas-to-metal ratio tuning maximizes spherical powder yield.
Melt Viscosity Shear
Meaning
Rheological behaviors under mechanical stress describe the changes in fluid resistance as a material undergoes deformation or flow. The melt viscosity shear defines the non-newtonian reduction in thickness that occurs in polymers and metal slurries during high speed injection. This property determines how easily a material fills the complex geometries of a mold.
Flow Dynamics
Molecules or suspended particles align with the direction of the flow when subjected to high pressure. This alignment causes melt viscosity shear to lower the effective resistance of the fluid. The effect is temporary and reverses once the mechanical force is removed.
Processing Stage
High injection speeds create high shear rates at the nozzle and the narrow gates of the mold. Managing melt viscosity shear prevents the thermal degradation of long chain molecules while ensuring the cavity is completely filled. Temperature also interacts with this force to change the overall flow profile of the melt.
Equipment Load
Measuring the pressure drop across a die provides a direct view of the rheological state of the material. Excessive melt viscosity shear can lead to localized heating and the burning of the polymer or binder system. Stable processing requires a balance between the speed of the injection and the thermal stability of the feedstock.
Correct nozzle geometry helps maintain this balance by providing uniform shear across the flow.