A CAD integrated analysis of flatness in a form tolerance zone

Abstract

Form tolerance plays an important role in representing features on a solid model. Reported research works on tolerance indicate that the current focus is on modeling form variations directly without defining the form tolerance zones. This paper presents a mathematical definition of the flatness tolerance zone using various parameters to describe its characteristics. By calculating the limits of these parameters, the size, location and orientation of the tolerance zone can be determined. Combining the flatness and size tolerance zones, a final zone can be obtained. This zone represents the actual region of space within which the toleranced surface must lie in order to satisfy both the size and form tolerances. The developed mathematical model is implemented in a 3-D modeling environment so that the user can specify tolerance types and values, and model the tolerance zones. This can be used in verifying the interference between parts during assembly modeling. © 2001 Published by Elsevier Science Ltd.