An analytical model for service level and tardiness in a single machine MTO production system
K. Altendorfer, H. Jodlbauer - An analytical model for service level and tardiness in a single machine MTO production system - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH, Vol. 79, No. 7, 2011, pp. 1827-1850
In many manufacturing industries, companies are facing more and more competition on the logistical service provided. For this reason it is important to improve the understand-ing of logistical relationships within manufacturing companies. The logistical relationship between production leadtime, utilization and WIP (work in progress) has already been discussed broadly in literature. This paper discusses the integration of the service level into the former mentioned logistical characteristic curves. A short overview about different methods used to calculate the service level is given. Based on these methods a model to calculate the service level based on the distribution of customer required leadtime, the coefficient of variation of production leadtime and on the inherent logistical relationships is developed for a one machine multi item production system. The logistical relationship is calculated for the M/M/1 and the G/G/1 situation in queuing theory as well as based on a recently developed continuous model. The com-bination with the continuous model leads to some advantages in computation and data requirements. A numerical example is presented and delivers further insights in maxi-mum possible service level as well as the influence of the relationship between WIP and FGI on the service level. The developed model contributes to the state of the art in production logistics since it describes the relationship between the production system, the FGI, the customer re-quired leadtime and the service level in a comprehensive way. Furthermore the model leads to a verification method for the current situation of real world production systems.