Patent US 5,963,881

In a system (12) wherein articles are manufactured by a plurality of process steps (20, 22, & 24), a method for identifying causes of variations in performance of the manufactured articles is provided. The method includes tracking orientation data (48) for the articles during each of the process steps (20, 22, & 24) and then measuring (50) performance data for each of the articles. The method also includes preparing surface performance characteristic maps (54) for each of the articles from the performance data and ordering the surface performance characteristic maps (56) for each of the articles in accordance with the orientation data for each article at a given process step (20, 22, & 24).