The Effects of Dimple Size and Depth on Friction Reduction Under Boundary Lubrication Pressure Available to Purchase

The effect of dimple size on sliding friction conducted under boundary lubrication conditions using a four-ball wear tester was investigated. The contact geometry used was a ball-on-three-flats arrangement using 52100 steel balls and flats. Circular dimples of various diameters (20–60 μm) and depth (2.5–10 μm) were fabricated using micro-lithography followed by electrochemical etching. Tests were conducted from 98–296N loads and 0.2–1.3 m/s speeds. Results suggest that smaller dimples with shallower depth achieve higher level of friction reduction under these test conditions.