Analysis of the Covariance Structure in Manufactured Parts

We discuss on a technological case study the use of estimators of covariance in a Kriging model to assess tolerances in a mechanical production process. It is a tricky issue to decide which class of covariance models is the best among the available options. The variogram is very informative about the spatial dependence and its estimation is essential in the spatial prediction, because it allows the computation of the weights assigned to the measured points in the Kriging prediction. In the paper we use various literature estimators for variograms for evaluating their estimation properties.