Ankara : Department of Industrial Engineering and Institute of Engineerin and Sciences, Bilkent Univ., 1998.Thesis (Master's) -- Bilkent University, 1998.Includes bibliographical references leaves 87-90.In the literature, scheduling models do not consider the unavailability
of tools. The tool management literature separately considers tool loading
problem when tool changes are due to part mix. However in manufacturing
settings tools are changed more often due to tool wear. In this research, the
problem of scheduling a set of jobs to minimize total completion time on a
single CNC machine is considered where the cutting tool is subject to wear.
We show that this problem is NP-hard in the strong sense. We discuss the
behavior of SPT heuristic and show that its worst case performance ratio is
bounded above by a constant. A pseudo-polynomial dynamic programming
formulation is provided to solve the problem optimally. Furthermore, heuristic
algorithms are developed including dispatching heuristics and local search
algorithms. It is observed that the performance of SPT rule gets worse as
the tool change time increases and tool life decreases. The best improvement
over the SPT rule’s performance is achieved by the proposed genetic algorithm
with problem space search.Güneş, Evrim DidemM.S
