Factories with a high production throughput and a low product variety traditionally choose a flow layout for mass production. The future market profile however will be volatile, customers expecting a larger choice in product diversity. Such a variable demand calls a new, flexible and reconfigurable production system, able to reconfigure in order to follow the market. This paper aims to present a method to modelize the production system permitting to identify the ways of improving the facilities on the reconfigurability criterion. Several reconfigurable assembly systems are proposed, targeting full load of the facilities. The specificity of the study consists in the consideration of both multiproduct and volume flexibility.