The Just-in-Time concept (JIT), first applied inside manufacturing facilities, has been extended to include supply chain components. This involves partnerships among manufacturers and their suppliers. A new trend in this relationship, at least in automotive and aeronautic industries, is that some hey suppliers are asked, not only to deliver the right parts in the right time, but also in the required order. We refer to this co-operation as synchronous. This paper presents a simulation-based approach for performance evaluation of tree-type synchronous manufacturing partnerships, with suppliers on the nodes and the manufacturer on the root. The approach involves two steps: global planning method, given the capacity of each supplier, simulation of part flows of a supplier or of the global organisation, given the planning and resources failures.