Supplying parts to mixed-model assembly lines is a complex logistic problem, often characterized by fatigue tasks and a low degree of automation. Emerging economic, ecological, and social challenges are forcing manufacturing companies to adopted internal material supply processes to these upcoming objectives and requires a fundamental change in system design of decentralized logistic areas. Based on a network of conventional and collaborative robots as well as a vertical-integrated system structure, this paper presents a novel concept to supply materials to mixed-model assembly lines for mass customized products such as electrical devices or automotive parts. The concept is derived, in a three-step design approach, from sustainable characteristics of logistic subsystems and enables new potentials in performance, flexibility and human-centric material supply for mixed model assembly lines.