For machined parts, setup time is a major component of the total time required to create a machined part. If the setup time can be reduced, this will not only decrease the machining time, but will also ensure better machining accuracy, require fewer work- holding devices and increase machine usage time.

To achieve any improvement in setup time, first we need to estimate the setup time accurately. In this paper we propose a methodology to estimate the setup time for machining prismatic parts in a three axis vertical machining center. We consider three major factors in estimating the number of setups, namely---the precedence constraints among machining operations, the feasibility of work holding using vise clamping, and the availability of datum faces for locating the workpiece.