The image shows the EHD2 tribometer from PCS Instruments. An enlarged view of the bath in the middle of the machine shows the ball in the oil pan beneath the glass Copyright: © MSE



Florian König

Head of Tribology


+49 241 80 20204



The EHD2 tribometer is a ball on disc tribometer from PCS Instruments that can be used to measure thin lubricant films, <200 nm, with a resolution of up to 1 nm and frictional forces in the elastohydrodynamic rolling contact, point or line contact. The EHD2 tribometer is generally used to compare different lubricating oils with each other with respect to their formation of a lubrication film and their friction. Greases can also be analyzed in addition to oils. Operating parameters can be set to Hertzian contact pressures up to 1.1 GPa, rolling speeds up to 4 m/s, temperatures up to 150 °C, and a slide-roll ratio up to 200 %. Variation of the parameters permits quantification of the effects on friction and lubricant film formation and thus the comparison between the lubricants. It is also possible to use the test results to determine key lubricant values, such as limit shear stress, for theoretical computation models.