practical measurement is provided by a laser interferometer attached to the table of the machine tool and a flat mirror clamped in the spindle (see Figure 1). Figure 1: The diagonal measurement set-up

2   Theoretical interpretation of the measurement According to the theoretical background of this method the measured volumetric error after each step of the sequence is influenced by three position error components. In the case of motion in the X-direction the error components are: Ex(x), Ey(x), Ez(x). These components are sensitive to all the motion errors including the position error, two straightness errors and three angular errors. It is possible to calculate and graphically display the course of the above mentioned error components for each axis after completing the whole measurement in four body diagonals of the working volume of the machine tool. In addition squareness errors in the xy, yz and xz planes can be evaluated. The measurement is in a direct relation with the ISO 230-6 standard, therefore the regular diagonal positioning errors are accessible for every diagonal and the parameters Ed (diagonal systematic deviation of positioning) and Bd (diagonal reversal value) may be calculated. A direct output of the results is presented by the generation of compensation tables for various types of control systems. The main advantage lies in the possibility to perform inter-axis compensation between all the machine axes from a single measurement. 3   The measured machine MCFV5050LN is the first Czech made machining center equipped with linear motor drives. A cross table with two driven axes X, Y and a vertically oriented