Meaning
Material properties that change based on thermal input dictate the ease with which a fluid flows through a system. As the heat increases, the molecules move more freely, causing the temperature dependent viscosity to drop rapidly in most polymers. This relationship is a fundamental consideration when setting the operating parameters of an industrial process.
Thermal Sensitivity
Some materials are much more reactive to changes in heat than others. A small adjustment in the barrel heaters can cause a large swing in the temperature dependent viscosity, which alters the pressure at the die. Understanding this sensitivity is required for maintaining a stable process and preventing sudden surges in output.
Process Influence
The way a fluid fills a mold or passes through a filter is controlled by its thickness at the point of contact. Because of temperature dependent viscosity, the cooling of the material at the walls of a die can create a frozen layer that narrows the flow path. This effect must be compensated for by increasing the melt temperature or the pressure of the pump.
Operating Range
Defining the safe limits for a process involves identifying the window where the flow is manageable without causing degradation. If the temperature dependent viscosity becomes too low, the material may lack the strength needed to hold its shape after exiting the tool. This balance determines the ultimate capability of a manufacturing line to produce consistent parts.
