Study of wear of diamond-coated probe tips when scanning on different materials

The accuracy of today's coordinate measuring machines (CMM) has reached a level at which the exact knowledge of each component is required. The role of the probe tip is particularly crucial because it is in contact with the sample surface. Understanding how the probe tip wears off will help to narrow the measurement errors. Today, diamond-coated probes of excellent quality are becoming commercially available. In the present work, the wear of those probes was studied when scanning on different sample materials and under different measuring conditions. The wear rate was quantified in terms of the rate of the removed diamond volume per meter scan length. It cannot be simply derived from material properties or scanning conditions. A simple calculation also shows that only a very small fraction of the friction energy is devoted to the removal of atoms from the diamond crystal. The wear rate of diamond-coated probes was found to be orders of magnitude smaller compared with the wear of traditional sapphire probes.