Joe Flow - Normal force control: May the force be with you
A measuring gap control via normal force is of great advantage in the measurement of semisolids like gels as well as solid samples. A gap adjustment is also required for many curing reactions.
What is normal force?
The term normal force refers to a force perpendicular to a surface. In rheology, this force acts on a sample (sample surface between measuring plates or cross-section of a solid bar). In old measuring methods, the axial load is often denoted as a mass. To calculate the normal force, this formula is applied: Mass [kg] = NF [N] / 9.81 [m/s2]
Example: The compression of a sample with a normal force of 10 N approximately equals a mass of 1 kg.
What to preset: normal force or gap?
The measuring gap is controlled
- either by normal force, based on a gap size measurement
- or by gap size, based on a measurement of the normal force.
Presetting both parameters makes no sense.