Division 5 ‘Stated “unidirectional positioning repeatability” ’ may be used for each machine tool model as an alternative to individual machine tests and is determined as follows:

Select five machines of a model to be evaluated;

Measure the linear axis repeatability (R↑,R↓) according to ISO 230-2:2014 and evaluate "unidirectional positioning repeatability" for each axis of each of the five machines;

Determine the arithmetic mean value of the "unidirectional positioning repeatability"-values for each axis of all five machines together. These arithmetic mean values of "unidirectional positioning repeatability" ( $\overline{\mathrm{UPR}}$ ) become the stated value of each axis for the model ( ${\overline{\mathrm{UPR}}}_x$ , ${\overline{\mathrm{UPR}}}_y$ …);

Since the Category 2 list refers to each linear axis there will be as many ‘stated "unidirectional positioning repeatability" values as there are linear axes;

If any axis of a machine model not specified in 2B001.a. to 2B001.c. has a ‘stated "unidirectional positioning repeatability" equal to or less than the specified "unidirectional positioning repeatability" of each machine tool model plus 0,7 μm, the builder should be required to reaffirm the accuracy level once every eighteen months.