M3 RENISHAW, Styli straight, ruby sphere, carbon fibre shaft
Spherical styli have the largest field of application because they have the same probing behavior in every direction. They are therefore suitable for all common measuring tasks such as measuring bores and surfaces. The larger the stylus sphere size, the larger the mechanical filter. This means that the profile of your workpiece is smoothened, which is often required in form measurement. The deviation from the ideal sphere shape is usually shown in Grade. ZEISS styli spheres have Grade 5 as standard, but can also be offered in a higher quality for special requirements.
Carbon fiber shafts represent an optimum combination of stiffness, weight, and thermal linear expansion. This makes them particularly suitable for long styli and demanding measurement tasks, such as in production with constantly changing ambient temperatures. They are also ideal for magnetic applications. The straight shaft is the simplest stylus design and the one with the longest usable length. The full shaft length can be used as measuring length. Carbon fibre shafts have the best thermal behaviour and the lowest weight, but a little less stiffness.
Ruby styli are the standard for almost all applications and are available in a variety of different diameters. Another advantage is that ruby spheres can be produced in very small diameters (from 0.12 mm). On the other hand, ruby has weaknesses at the continuous scanning of certain materials and surfaces. 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 sphere changes as a result and loses accuracy.