Design of an isotope separation cascade is often accompanied by minimizing the total flow in it to provide given concentrations of the target component in the product and the waste flows. This task is hard because the minimization deals with a multi-variable optimization of mixed integer and real type variables. In the present work, introducing a parameter M in the calculation of Q-cascades as the only optimization variable develops a new optimization approach. Numerical tests are carried out for separation of the isotopes Cd-114 and Cd-116, respectively, and the results show that optimum cascades with minimum relative total flow for multicomponent isotope separation can be easily found with this new approach. (C) 2010 Elsevier Ltd. All rights reserved.