Automated Meter Mix Dispensing Dynamics for Thermally Conductive Gap Fillers
Volumetric displacement precision, shear rate thermal control, and wear-resistant fluid metering govern automated thermal gap filler dispensing performance.
Non Newtonian Fluid Mechanics
Meaning
Fluid dynamics studies the behavior of materials whose viscosity shifts depending on the rate of applied shear. The principles of non Newtonian fluid mechanics govern how thermal pastes and filled adhesives flow during manufacturing. Understanding these relationships is necessary to design effective pumping and dispensing systems.
It allows engineers to predict flow behavior under high pressures and narrow geometries.
Shear Behavior
Most filled battery materials exhibit shear-thinning behavior, meaning their viscosity decreases as the flow velocity and shear rate increase. This property allows highly filled pastes to flow easily through narrow nozzles during extrusion. Once the shearing force stops, the material recovers its high viscosity, preventing the deposited bead from slumping or spreading out.
This rapid recovery is essential for maintaining the shape and position of dispensed thermal materials.
Dispensing Effect
High shear rates inside dispensing valves can cause unexpected flow resistance if the material is shear-thickening. In such cases, viscosity increases with shear rate, which can lead to clogged nozzles and damaged equipment. Predicting these transitions requires a detailed understanding of how the filler particles interact within the polymer matrix.
High concentration of ceramic particles often increases the complexity of the fluid response.
Rheological Analysis
Rheometers measure viscosity across a wide range of shear rates to generate flow curves. These curves are used to select appropriate pumps and configure dispensing parameters.