Simulation modeling is one of the most important methods used in the manufacturing processes field. The purpose of using the simulation processes is to determine the problems that happen during manufacturing processes and find optimum solutions with better cost and time process. The simulation processes always happen before start applying processes in the plant. This research focuses on finding optimum solutions to the problems in the production lines such as a bottleneck and processing time at each station of the plant. Also, the research will focus on increase productivity of the plant by running simulation models several scenarios in order to reach the optimal case. Arrival time, capacity, expo time are parameters that will study and consider in each station to avoid problems in the plant. In addition, this research will use a design of experiments DOE and response surface methodology RSM to analysis and support the results and find the optimal mathematical model of the production line. Finally, the steepest ascent method will use to determine the optimum region and give a specific point of the optimizing of results.