M5, spherical cylinder styli, ruby cylinder, tungsten carbide shaft
Cylindrical styli measure two-dimensionally and are particularly suitable for narrow workpieces, such as thin sheet metal. Even narrow workpiece edges can be measured well with cylindrical styli. Care must be taken to ensure that the styli axis is mechanically aligned very precisely with the feature axis on the workpiece. A special form are the spherical cylindrical styli, which are mostly used for sheet metal measurement and measurement at sheet metal edges. They have a spherical end and can thus additionally determine the flatness of a surface, for example.
Tungsten carbide is the most common shaft material, it combines a very good stiffness with an acceptable thermal expansion. Only the weight can have a negative effect when using large styli. The usable length is described by the value B and differs from the value ML. Tungsten carbide shafts represent a good combination in terms of weight, rigidity and thermal expansion.
Ruby styli are the standard for almost all applications and are available in a variety of different diameters. By scanning certain materials and surfaces, Ruby shows weaknesses due to material deposits and wear. With extremely soft materials, e.g. aluminum, material from the workpiece can be deposited on the ruby surface (material deposit). Very hard and rough surfaces, e.g. castings, on the other hand, cause abrasion of the sphere (material removal). The shape of the cylinder changes as a result and loses accuracy.