In this paper, we present a prototype of an intelligent PLM system for machining environment. This PLM was developed for optimal configuration and layout design of unit-head machines which are used in the mass production of a unique product or a family of similar products. In these machines, the machining operations are executed on working positions equipped by standard modular spindle heads. The part is transferred from a working position to the next one by means of a movable table (rotary or mobile). The machine configuration defines the machine productivity and the final machine cost. The paper depicts all mathematical and decision-aid methods developed and implemented in the PLM for optimization of machine configuration.