This paper introduces a business process simulation (BPS) model of a purchasing process in a research-manufacturing company. Then, this model is used to introduce and evaluate several improvement and business process re-engineering (BPR) models. The users of the purchasing management verify that the goals of a BPR model are to create a process-oriented approach in order to reduce purchasing process cycle time, faster customer response time, and lower cost. The conceptual model of the business process is developed by an integrated definition for function modeling (IDEF0). The associated process times are collected by standard time study and then analyzed by a statistical analysis. In addition, the computer simulation model of the process is developed by the Visual SLAM software, in which this model is verified and validated by F-test and t-test. Two scenarios are proposed according to the BPR concepts showing more efficiency than other scenarios. The first model is compromised by using only information technology (IT) and information engineering. In the second model, the process is designed by using the Davenport's approach as process designing as well as using organizational, human resource, and IT enablers. Finally, the proposed models are analyzed using the trade-offs analysis and then the BPR model by using the enablers is chosen as the best model.
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