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

Abstract

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.

Surface-Sensing Principle of Microprobe System for Micro-Scale Coordinate Metrology: A Review

“…A large measuring force can damage the measurement surface [38]; therefore, the probing force is one of the important specifications. A large measuring force induces other influences such as probe tip wear during scanning measurement [39,40]. The measuring force must be considered in terms of stress, e.g., if the probe tip diameter is reduced to 1/10, the contact area will be reduced to 1/100, thus resulting in 100 times more stress on the measurement surface.…”

State of the Art of Tactile Micro Coordinate Metrology

“…Not only effects of surface indentation due to measurement forces [2], but also stylus wear and deposition of wear debris on the probe sphere become relevant [42]. These effects can be significantly reduced by selection of appropriate materials for the probe sphere, e.g., diamond coated spheres [43].…”

Design and Applications of Coordinate Measuring Machines

“…A number of standards have been developed worldwide. Most of them look like a miniature version of popular artefacts applied in large CMMs, for instance, mini ball bar [43], mini ball array [44] or mini ball plate. Photos of some representative calibration artefacts studied at PTB are illustrated in Figure 8.…”

“…Not only effects of surface indentation due to measurement forces [2], but also stylus wear and deposition of wear debris on the probe sphere become relevant [42]. These effects can be significantly reduced by selection of appropriate materials for the probe sphere, e.g., diamond coated spheres [43].…”