M5, Hollow hemisphere stylus, ceramic
Hollow hemispherical styli consist of a stylus tip that has been cut off above the equator, in addition, the remaining part of the sphere is partially eroded. The reason for this is a weight reduction, especially for large-diameter spheres, which can save up to 70% of the weight. Hollow hemispheres are produced using a complex manufacturing process in order to achieve maximum weight savings.
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 straight shaft is the simplest stylus design and te one with the longest usable length. The full shaft length can be used as measuring length. Tungsten carbide shafts represent a good combination in terms of weight, rigidity and thermal expansion.
Ceramic is a very light material and is therefore mainly used for styli spheres with large diameters. Ceramic discs have a very low porosity and a high-precision. They are particularly suitable for scanning rough surfaces such as cast iron