TThe EHD2 Ultra Thin Film Measurement System is the latest evolution of the PCS´ successful EHD instrument. It is now a fully automated computer controlled instrument for measuring the film thickness and traction coefficient (friction coefficient) of lubricants in the elastohydrodynamic lubricating regime. EHD can measure lubricant film thickness down to 1 nm with a precision of +/- 1 nm. The contact pressures and shear rates in this contact are similar to those found in, for example, gears, rolling element bearings and cams. In addition to film thickness measurements, traction coefficients can be measured at any slide/roll ratio from pure rolling up to 100%.
The instrument measures the lubricant film thickness properties in the contact formed between a ¾“ (19.05mm) diameter steel ball and a rotating glass disc by optical interferometry. The lubricant film thickness at any point in the image can be accurately calculated by measuring the wavelength of light at that point. Normally the system measures the wavelength of the light returned from the central plateau of the contact and hence calculates the central film thickness.
Features and Benefits
- Evaluation of film forming oils and greases
- Starvation and reflow characteristics of grease lubricated components
- Fuel economy prediction of candidate crankcase oils
- Performance prediction of oil in water emulsion rolling mill lubricants
- Fundamental investigations of the high pressure/high shear behaviour of fluids such as liquid crystals
- Investigation of boundary additive performance