The flow of a production system is successively limited by its bottlenecks. To get the maximum possible effect from improvements to the system all bottlenecks must first be identified and ranked based on their importance. Thereafter can different solutions for improvement be considered based on estimated effect and implemented. Theories relating to processes, lead time, production rate and simulations have been used in this study to get a better understanding of flow optimization and the production system. Quantitative values have been found for all machines in the system. With the use of simulation software these values have been used to identify bottlenecks and which areas that need improvement. The company at which the study took place wanted to know how the implementation of a new machine would affect the efficiency of the production. The flow of the production system was compared to a simulation with the suggested changes. The study showed that the throughput of the system increased by 11,7% after changing this machine, if the machine always has material to process. The study also showed earlier machines in the production line could not supply this machine with enough material and suggestions on how to improve this was made.