Experimental pre-rolling friction determination of corundum balls on silicium wafers using highly stable pendulum

The pre-rolling coefficient of friction is determined using a method based on theoretical model for various contact material interfaces. In this experiment, a designed two-ball based pendulum oscillating on flat material is used in a pure rolling without any mechanical or physical effect on the rolling and on pre-rolling in particular. The induced micro-slippage as assumed by Kalker is eliminated in this work through the pendulum design. The experiments have shown low values of pre-rolling coefficients for various combinations of materials e.g. Alumina on Silica or glass materials. Moreover, the experiments have shown that as the surface roughness increases the oscillations time of the pendulum decreases exhibiting direct effect on pre-rolling.