A case study from company that involved in the electrical and electronic manufacturing industry is presented in this paper. The manufacturing operation consists of several workstations that form an assembly line to make magnetic electronic products. Excess work in process inventory, unnecessary movement, over processing, and waiting time are identified as non-value-added activities across the process value stream. Meanwhile process cycle time, pieces per man hour, and manufacturing lead time are selected as a performance measures. A comprehensive discrete event simulation model was developed to replicate the existing assembly process. It then been utilized to optimize the interactions among the elements by focusing on minimizing the mentioned waste, to analyze improvement opportunities, and to quantify the possible benefits of the proposed actions. The information obtained from the computer simulation experiments, allows the management of the case study company, a real time perspective of how lean manufacturing implementation affect the performance measures. Besides, it may also reducing the risks associated with making decision in tweaking the current process through improvement activities.