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In order to adapt to a rapid changes of manufacturing orders, flexible manufacturing systems (FMS) advances into the direction that machines become further versatile functionally and that tools are controlled by fast tool delivery device. Versatile machine can perform a variety of operations when it is supplied with the required tools. Tool management is among the essential elements in the successful operation of the FMS studied in this research. In this research, we propose an integrated model that performs operation sequence and tool selection simultaneously into the direction that minimizes tool waiting time when the tool is absent. The effectiveness of the model is demonstrated through a series of simulation experiments, and interpretations of the results are also presented. Keywords: Dynamic tool allocation strategy; Tool movement; Tool waiting time; Operation sequence

Given the plant layout, the number of workers, the maximum number of machines that a worker can handle, and the preferences between each worker and each machine, the problem to minimize the deviations of workloads assigned to workers and to maximize the total preference between each worker and each machine is considered in the semiconductor industry. The number of workers is fixed (no part time workers) because of the high expense of technology education and the increase of current employees. Since the workforce assignment problem in this article is in NP class, several heuristic algorithms are presented according to two types of plant layouts during two types (slow and peak) of periods. The proposed algorithms are developed based on the combination of a mixed model scheduling, simulated annealing technique and graph theory. The solution generated satisfies the zone constraint (machines assigned to a worker are adjacently located). Computational results show that the presented algorithms can find a good solution quickly.