Surface error decomposition for fixture development

As an integrated element of the manufacturing system of components, the machining fixture is a major contributing factor of the profile and orientation errors of component features. An effective way to control the accuracy of components is to decompose error sources and evaluate individual influential factors. This paper proposed a systematic method of error identification and calculation, in which locating error and machining error were studied. The locating error, which is the surface error generated before machining, is obtained from the calculation of the surface error based on tolerances of the locating positions and the decomposition of clamping deformation using finite element analysis (FEA). The machining error, the surface error generated from machining operations, is gained mainly from the coordinate measurement machine’s (CMMs) measurements. The surface error of multi-machining operations is investigated and the resultant surface error is evaluated against tolerance. The analysis of a sample feature of a turbine blade is provided as an example.