Indicators for measuring performances of morphology and material handling systems in flexible manufacturing systems

The aim of this paper is to present some existing and several new indicators of performances useful to help the designer to find a good solution for morphology and choice of material handling systems in flexible manufacturing systems. Our purpose here is to focus on the evaluation of the pair morphology–material handling systems, studied concurrently due to their strong interdependence. As a result of a survey of literature in this area, we present in this paper the indicators we have retained as suited to this purpose and easily implemented. New indicators related to the performances of these systems, such as the flexibility, are also suggested. A classification of indicators is introduced: (1) the operational indicators, which characterise the dynamic behaviour of the studied FMS such as the mean flow-time of jobs or the utilisation rates of machines; (2) the strategic indicators which measure the capacity of the system to evolve toward manufacturing new products such as the flexibility on which the emphasis is put; (3) the economic indicators such as the purchasing cost, the functioning cost or the maintenance cost. To better introduce the role, the usefulness of each indicator and their practical use, an illustrative example is presented.