A. R. Valdés, A. Piratelli-Filho, D. P. Vieira Sato
UNCERTAINTY OF COMPONENTS OF VOLUMETRIC ERRORS
The aim of the present work is to calculate the uncertainty associated with volumetric error components in a Moving Bridge type Coordinate Measuring Machine (CMM). Two methodologies are presented for this purpose. The first consisted in equationing the components of the volumetric error using homogeneous transformations techniques; measurement of the geometric errors and Abbé offsets; mathematical models regarding each geometric error and Abbé offset were written and the law of uncertainty propagation was applied. The second methodology present simplified models to estimate the measurement uncertainty associated with volumetric error component, identifying the variables that influence the determination of geometry deviations, development of a mathematical model for the volumetric error components, development of a routine to evaluate uncertainty. It was concluded that the simplified models are adequate and easy to be applied. As conclusions, the components of volumetric error of X, Y and Z axes present uncertainty values close to 2.7, 4.0 and 2.0 mm, respectively.