A study on tolerance design of machine tool components based on shape generation motions

Abstract

The kinematic motion deviations of the five-axis machining centers are deeply influenced by the geometric deviations of the components, such as guide-ways and bearings. A systematic design method is required for specifying suitable geometric tolerances of the guide-ways, in order to improve the kinematic motion deviations of five-axis machining centers. The objective of the present research is to establish a computer-aided design system for specifying a suitable set of the geometric tolerances of the guide-ways considering the trade-off between the requirements on the kinematic motion deviations and the ease of the manufacturing processes. A mathematical model was proposed in the previous papers to represent the standard deviations of the shape generation motions, based on the tolerance values of the guide-ways of the five-axis machining centers. A systematic method is proposed here, by applying an optimization method, to determine a suitable set of the tolerance values of all the guide-ways under the constraints on the kinematic motion deviations between the tools and the workpieces. The method is applied to some design problems of the geometric tolerances of the guide-ways included in the five-axis machining centers.

Keywords

• machine tools
• five-axis machining centers
• shape generation motions
• geometric tolerances
• tolerance design
• design optimization