The stylus is an important part of the measuring system. During the measurement, the stylus is in direct contact with the part. Straight styli are the most common type used in the metrology industry. Depending on the application, different materials for stems and tips are available.
Silicon nitride styli tips have similar material properties to ruby whilst being more wear-resistant. Silicon nitride does not tend to form material build-up while scanning. Because of this, it is recommended for measurements on aluminium parts.
A tungsten carbide stem has high stiffness and less thermal expansion, compared to stainless steel.