A geometric errors analysis method integrated clamping error and wear out error over working space

Abstract

Machining accuracy is one of the major parameters of machine tools which is determined by geometric accuracy design to a large extent. In order to improve the comprehensiveness and veracity in geometric accuracy design, this paper proposed a geometric errors analysis method integrated clamping error and wear out error over working space. A multi-rigid-body model which included the cutting tool's wear out error and work-piece's clamping error is established to represent the position relationships of machine tools' working components. The expression of geometric error was converted from matrix form to screw form through a screw mapping method so that geometric error of all the six degree of freedom in global coordinate frame can be straightly expressed. Based on this, the key geometric errors that affecting the machining accuracy were identified through the improved sensitivity analysis in which motion rules through working space were considered. Finally, a case study on geometric accuracy design stage of a horizontal boring machine was carried out which highlights the advantages of the proposed methodology.