This Section establishes the principles of identifying features of a part as datum features for the purpose of establishing geometric relationships imposed by a feature control frame. Datums are theoretically exact points, axes, and planes. These elements exist within a framework of three mutually perpendicular intersecting planes known as the datum reference frame. See Fig. 4-1. This Section also establishes the criteria for establishing datums and the datum reference frame from datum features.
Was this article helpful?