This paper presents a comprehensive simulation project in the area of an automotive supplier. The company produces car styling serial and original accessory parts made from plastic for internal and external applications in passenger cars. For the foaming division, which is identified as the bottleneck, different personnel and qualification scenarios, set-up optimizations and lot-sizing strategies are compared with the current situation. Key performance measures reported are inventory, tardiness and service level. The changes in organizational costs (e.g. employee training, additional employees, etc.), due to the scenarios, are not considered and are traded off with the logistical potential by the company itself. Results of the simulation study indicate that a combination of an additional fitter during night shift, minor reductions of set-up times and reduced lot-sizes leads to an inventory reduction of ~10.6% and a service level improvement of ~8% compared to the current situation.
Manufacturing plant simulation for production and workforce planning
A wide range of publications concerning MRP (material requirements planning) as planning a method are available showing that MRP is applied in industry and intensively studied. MRP can handle any kind of complexity and stochastic behavior in customer demand and processing time, which supports its enormous popularity among industry. Among others, one of the main parameters for MRP is the lot-sizing decision influencing inventory, set-up effort (and therefore utilization) and service level. Recent work on lot-sizing discusses, for example, customer demand variance, solution algorithms, set-up influence and simulation for lot-size optimization. In this study, simulation is also applied to identify the influence of lot-sizes in the investigated production system.
In this paper, we examine the foaming division of an Austrian automotive supplier. The production planning and control method for the materials is MRP. The sales plan of the last business year is input for all investigated simulation scenarios. The validation process is twofold. On the one hand, performance measures from the simulation model (inventory, work in process (WIP) and service level) are compared with the ones of the last business year. On the other hand, we conduct in depth analysis of the manufacturing simulation model with the company partners. The production area has three production stages (foaming, manual trimming one and manual trimming two). The target of the study is to compare different personnel and qualification scenarios on a manufacturing facility with simulation, set-up optimizations and lot-sizing policies with the past business year and provide managerial insights. There are analytical models for all of these decisions available, however, simulation is a convenient tool to handle the complexity of the combination of these decisions and is therefore applied in this study.