  This work is concerned with providing a principled decision process for
stopping or tool-changing in a surface finishing process. The decision process
is supposed to work for products of non-flat geometry. The solution is based on
conducting hypothesis testing on the bearing area curves from two consecutive
stages of a surface finishing process. In each stage, the bearing area curves,
which are in fact the nonparametric quantile curves representing the surface
roughness, are extracted from surface profile measurements at a number of
sampling locations on the surface of the products. The hypothesis test of these
curves informs the decision makers whether there is a change in surface quality
induced by the current finishing action. When such change is detected, the
current action is deemed effective and should thus continue, while when no
change is detected, the effectiveness of the current action is then called into
question, signaling possibly some change in the course of action. Application
of the hypothesis testing-based decision procedure to both spherical and flat
surfaces demonstrates the effectiveness and benefit of the proposed method and
confirms its geometry-agnostic nature.
