What is the minimum and maximum thickness of oil film that can be measured?
A10. There is no upper limit to the thickness that can be measured. Using conventional transducers we can measure oil films down to around 100 nm. Using higher frequency transducers it is possible to measure down to around 20 nm. But with higher frequencies and very thin films, the signal noise, and attenuation become more of an issue and care has to be taken. In practice hydrodynamic bearings like journal and thrust pad bearings have films in the range 0.001-0.1 mm whereas elastohydrodynamic bearings like ball and roller bearings have films in the range 0.0001-0.001 mm. The Ultrasensor system can cover this entire range.
