A Simulation Modeling Approach for Job Shop Scheduling Problems: Case of Metal Industry

In most of the manufacturing units job shop scheduling is a difficult task due to the complexity of the system. Job shop scheduling problem (JSSP) is very important and has a lot of application in industrial and service sectors. To maintain the good job shop scheduling, facilities can save time and money. A case study was conducted on a metal Industry located in Ethiopia. In metal and engineering company is facing a job shop-scheduling problem in its spare part manufacturing plant. The higher make span (lead-time) to produce parts resulted from conventional scheduling is dissatisfying customers and causing low machine utilization. This study aims at reducing make span and improving the performance of the manufacturing system. The data collected from the case company to get the time taken by the conventional scheduling method and also gathered data for four jobs requiring five machines that arrived during the research period. The proposed method Arena simulation software used to find the shortest processing time (SPT) was found to be the optimum for the five performance measures. The results indicate that by using the SPT dispatching rule the make span was reduced from 25 hours to 19 hours with 24 % improvement.