Optimization of the nibbling operation on an NC turret punch press

Abstract

The fabrication of sheet metal parts on an NC turret punch press is accomplished by first punching the desired holes in the parts nested on the sheet stock followed by nibbling the boundaries of the parts in order to separate them from the sheet. This paper addresses the problem of minimization of the total time taken for the nibbling operation for a given sheet configuration of nested parts. Finding a solution to this problem requires the solution of two coupled sub-problems, namely the part sequence determination problem and the pierce point determination problem. In this paper, we present two approaches to optimizing the nibbling operation and discuss their performance on sample data sets. The incorporation of the proposed optimization scheme within CAD/CAM systems will lead to reduced processing times and more effective utilization of NC turret punch presses.