Tool handling synchronization in flexible manufacturing cells

Some optimization models for the problem of tool management in flexible manufacturing cells are presented. The cell considered consists of two machines (working centers) in charge of executing a set of part programs. The tools required by the machining operations are located in a central tool magazine and are moved to the machines by a tool handling system consisting of two shuttles and one robot. The robot picks and places the tools from/in the magazine; each shuttle exchanges the tools with the robot and with the machine. The problem is to synchronize the robot and shuttle moves in order to maximize the cell productivity (minimize the machines´ idle time). Two different models are proposed for the situation in which a configuration of tools in the magazine is given and in which a budget for tool purchasing is fixed