Identification of Alignment Errors in Five-Axis Machining Centers.

Abstract

This paper deals with the theoretical identification of alignment errors for five-axis machining centers. The form-shaping function which takes geometrical errors into account is theoretically derived for the error analysis of precision machine tools. The relationship between error sources and machined error is expressed by using the transformation matrices. In the five-axis machining center, errors in the relative position between the workpiece and the cutting tool directly affect the accuracy of the operation being performed. This positional error originates from numerous factors including geometrical errors of the structure elements, kinematic errors related to the motion of these elements, or thermally induced errors, static and dynamic deflection, etc. Alignment errors have basic effects on the machining error. In this paper, therefore, the effect of alignment errors is clarified by using the form-shaping function. Assuming the use of a double-ball-bar device, the measurement method for alignment errors in a five-axis machining center is proposed. Additionally, eleven (11) alignment errors in a five-axis machining center can be identified from measured values obtained by double-ball-bar.