In injection molding, the viscosity describes the flow resistance of the plastic in the cavity.
Higher slow-moving of the material means higher viscosity.
Flow curves show that the viscosity of a plastic varies by different shear rates and temperatures.
These curves need to be measured with the help of a viscometer or rheometer.
The viscosity is described by the formulaic character 𝜏 (Tau).
Its unit is Pascal seconds.
Examples of Viscosities:
Water: 0,001 Pas
Oil: 0,03-0,1 Pas
Glycerin: 1,5 Pas
Honey: 10 Pas
Easy flowing plastic melt: 1000-5000 Pas
Heavy flowing plastic melt: 10000 – 100000 Pas