Before the styli can be used for measuring, they have to be qualified. This is necessary to allow the measuring software of the CMM to calculate the exact position of the stylus sphere and the exact stylus sphere diameter as a function of shaft length, stylus structure, etc.:
In the first step, the master stylus (whose exact geometric data
is known to the measuring software) is used to the measure the reference sphere. Once this has been done, the measuring software knows the exact position of the reference sphere.
In the second step, the individual styli are qualified. This is done by probing the reference sphere in approximately 25 probing points using each stylus. Since the measuring software knows the sphere diameter, it is able to calculate the stylus data. Important: Between the first and second step, the position of the reference sphere must not be changed, otherwise all stylus calculations will be wrong!
When in use, the coordinate measuring machine is usually not switched off at the end of the shift, but rather handed over to the next shift. To ensure that the metrologists of the next shift know whether and when the styli were qualified, it is absolutely necessary to log each qualification indicating the stylus designation, stylus sphere diameter, date, time, qualification log and user name.
