8. Conclusions Working with DES and automatic data collection is a beneficial way of increasing equipment efficiency of a manufacturing system. A case study at a larger manufacturing system has shown the method of bottleneck reduction. An increase of availability from 58.5 to 60.2 percent in a single machine showed an overall increase in the system of 3 percent after the improvements were implemented in a system with 21 different operations. One year later the overall output in the system has risen 6 percent compared to the beginning of the project. The main advantage of the DES model is that all experiments can be carried out off-line and do not disturb the actual manufacturing. The results from the experiments can be used as feedback for evaluations of the manufacturing system. In future manufacturing systems more automatic data will be provided. The data can be used to bottleneck analyses in a manufacturing system with the help of DES according to the described methodolog