An imprint method to produce surface asperities for EHL and RCF experiments

A method was developed for creating single well-defined surface asperities using an imprint technique. The proposed method enables: • Creation of well-defined micrometre high asperities; • Creation of asperities which survived more than 35 million EHL contact cycles; • Damage tracing thanks to the possibility to control the damage initiation sites. The technique is based on rolling a hard disc with indents against a soft disc for creating single surface asperities. The contact pressure causes plastic deformation forcing material into the indents to create the asperities. The height of the asperities can be controlled by adjusting the applied force. After initial reshaping during the run-in process, the asperities were strong enough to survive more than 35 million elastohydrodynamic lubrication cycles, which should be of great interest for the researchers who investigate rolling contact fatigue experimentally. The method could also aid the research on the run-in process by enabling tracing the development of specific surface defects. Since the method can produce high and strong asperities it might also prove useful for investigations how asperities deform under sever contact conditions.