The concept of “customer driven production planning” for evaluation of job-shop system performance
K. Altendorfer, H. Jodlbauer - The concept of “customer driven production planning” for evaluation of job-shop system performance - Proceedings FH Science Day 2006, Hagenberg, Österreich, 2006, pp. 139-149
Motivation: The decision to organize production according to “make to stock” (MTS) or “make to order” (MTO) principles is important since it influences finished goods inventory enormously. To evaluate if a production system is able to be run under MTO with zero percentage late jobs the concept presented by Jodlbauer (2006) in “Customer driven production planning” is used. Further some additional information about the performance of a production system which is not able to install a pure MTO system is derived from Jodlbauer`s work. This additional informa-tion is the minimum percentage of late jobs which could theoretically be reached by the pro-duction system if it is run under MTO, and how much additional capacity would be needed to be able to install an MTO system with zero percent-age late jobs.
For a specified job-shop production which is, according to the evaluation based on Jodlbauer, not able to install an MTO system, the minimum percentages of late jobs for different levels of average due dates are calculated corresponding to the methodology presented in this paper. For these levels of average due dates used to calcu-late the delivery reliability, simulation runs are performed and the simulation results are com-pared to the results according to the presented methodology. Jodlbauer`s paper focuses on flow-shop productions with low variations on the shop floor and predefined paths for the products through the production. The simulated job-shop production in this investigation is characterized by flexible paths of the products through the shop floor and has high variations in the time for production as well as many disturbances through machine breakdowns. The simulation model of the job-shop production was created as part of the master thesis by one of the authors.
Results: The analytical evaluation, if the speci-fied job-shop production system is able to work under MTO with zero percentage of late jobs, according to Jodlbauer`s methodology is proven to work well, also the evaluated production sys-tem is more complex than the production system Jodlbauer based his work on. The additional in-formation about system performance, which is the minimum percentage of late jobs, derived from Jodlbauer`s paper proves to be a good esti-mator for this number. The evaluated system with the production planning and control (PPC) parameters used for simulation shows a much lower performance.