The productivity factor, and the economical effect factor are both very important for operation of a flexible manufacturing system. Both follow from a high purchase cost of the equipment for FMS. When we want to assure reliability of FMS then a prescribed number of spare or alternative resources, respectively are needed. Most spare resources can be estimated by the coefficients of flexibility.
This paper is concerned about the possibilities of evaluation of flexibility of flexible manufacturing system. This method defines the flexibility coefficient on the basis of FMS units, tools and working accessories. The result obtained is the flexibility coefficient. This method of estimation, gives us the possibility of simple evaluation of resources in which future investment will be made. The paper also indicates the possibilities of use of this coefficient. The presented way of evaluation of flexibility can be used statically from case to case. However the module for evaluation of the coefficient can be included in the operating system and the evaluation followed up dynamically.