Throughput sensitivity analysis in closed loop manufacturing systems for hairpin stator production

With the development of the electrical vehicle (EV) field, multiple closed loop manufacturing systems (CLMS) handling will have a predominant role in near future industry, since they are used to produce key elements of EVs. Nevertheless, literature for multiple CLMS is not wide and developed. This work is developed from an industrial case of multiple CLMS in EV industry. Through the system analysis, a phenomenon called near flatness (NF) arouse our interest. It identifies the capability of a CLMS to keep a nearly constant throughput when the number of items circulating in the CLMS varies. Further analysis about the relationship between NF and system parameters is carried out. Numerical results, obtained through discrete event simulation, show that NF phenomenon is related to the efficiency in isolation of the machines and the balancing in terms of system processing time. Finally, practical guidelines for multiple CLMS handling, related to NF, are provided.