Experimental and Numerical Studies of the Influence of Geometric Deviations in the Performance of Machine Tools Linear Guides

AbstractThe main goal of this research work is to investigate and characterise the geometric accuracy and its effect on the performance of the guiding system in machine tools or CMMs. As geometric errors are one of the main sources of the volumetric errors in manufacturing systems, it is necessary to carry out a comprehensive geometric measurement of their components such as guiding systems. Lack of care during assembly can cause some kinds of errors in the guides and other components which may lead to over-determination of the system. In this research, some pre-defined geometric deviations in horizontal, vertical and both directions are applied to the guides and their corresponding influences on the accuracy are recorded. Straightness measurements in horizontal and vertical planes, and also roll, pitch and yaw angular measurements are carried out as a function of axis position. The motion errors of a typical ball bearing linear guide with a slide mounted on four carriages are analyzed. Except for the roll angular measurements which are conducted using electronic levels, all the other ones have been carried out employing laser interferometry method. Various locations of the slide are measured to find out the role of position for straightness and angular measurements. FEM simulations have been then used to model the experiments. Good agreements between the experimental and numerical results are observed. The location of the work-piece on the slide also has an important role for various motion errors