A Mathematical Model and Solution Methodologies for Optimal Process Planning on Four- Axis CNC Turning Centers

Abstract

A new generation of Computer Numerical Control (CNC) machines, called four-axis turning centers has emerged and has been growing in use due to its versatility. Multiple turrets and spindles, automated material handling, and mill/turn capabilities on these machines enhance their processing capacity and lead to substantial improvement both in quality and productivity for turned components. However, optimal process planning on these machines is considerably complicated by their improved capabilities. No current commercial Computer-Aided Process Planning (CAPP) systems have considered constraint generation or process plan optimization for this class of machines. In this paper, the optimal process planning problem for four- axis turning centers is formulated as a Mixed- Integer Programming (MIP) model. The formulation is coded in GAMS (General Algebraic Modeling System) modeling language and the Branch- and- Bound (BB) algorithm is used to solve the problem. Experimental results with BB are presented as well as a comparison of results obtained from additional experiments with a partitioned-based heuristic, the Nested Partitions algorithm (Chalermdamrichai, Veeramani, and Shi 1999).