Model-based derivation of a generally valid approximation of characteristic curves for WIP and utilisation

• Applicant: Professor Dr.-Ing. Hermann Lödding
• Subject Area: Production Systems, Operations Management, Quality Management and Factory Planning
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 415040468

Production operating curves describe the quantitative relationship between mean work in progress and mean workstation utilization. Queuing theory formulates an exact mathematical relation. Since this theory assumes rigid capacities and loads, the applicability in industry is limited. Nyhuis’ operating curves provide a practical model for production that takes capacity and load flexibility into consideration, however implicitly using an empirical factor.The goal of the research project is a generally valid modelling of operating curves that describes the relation of work in progress and utilization as a function of process time and interarrival time distributions and capacity and load flexibility. On the one hand the resulting synthesis will enlarge the scientific understanding of the modelled relationships. On the other hand the results will enable companies to dimension work in progress, utilization and throughput times more accurately. In particular, companies can use the model to assess the effect of measures that change capacity and load flexibility.

• DFG Programme: Research Grants