This paper reports the finding of a new type of cascade, named as net cascade, which achieves no-mixing of concentrations at any confluent point in multicomponent isotope separation. A method of realizing no-mixing is described in detail. The idea is that the cuts at a stage calculated from all components should be identical, which imposes conditions on the choice of separation factors. Solving the equation system resulting from these conditions gives the appropriate choice. Taking the separation of tungsten hexafluorideas an example, a no-mixing net cascade is constructed. Other properties of the net cascade are studied preliminarily.