Title: OPTIMAL TOOL MODULE DESIGN PROBLEM FOR NC MACHINE TOOLS
Abstract: In order to enhance factory automation and unmanned production, numerical controlled (NC) machine tools are widely used in many mechanical processing factories. Whenever one machining part is changed to another, the operation of an NC machine tool has to be stopped in order to change some of the cutting tools on the turret tool holder. In this paper, a new concept of 'tool module' is used and the problem of reducing the number of tool changing operations for NC machine tools is discussed. The problem is formulated as a 0-1 integer programming (0-1 ILP) problem on a bipartite graph and a branch and bound algorithm is proposed to select an optimal tool module. Since the LP relaxation problem obtained by dropping the integrality condition for the 0-1 ILP problem has a special network structure like the well-known transportation problem, this LP is solved by certain network flow algorithm with utilizing its special structure Some numerical experiments are reported, and indicate that the algorithm is reasonably efficient. Furthermore, possible extensions of this method are discussed.