Collaborative robots becomes more and more common in lab environment and soon also in industry. In order to create resource-and volume flexibility, dynamic and smart automation could be seen as an answer. This paper has investigated the collaborative robots UR3 and UR5 for O-ring assembly and final assembly, compared to the current state which is performed manually. The methodology Dynamo++ was used for measurement and analysis in terms of LoA (cognitive and physical), cycle-time and quality. Furthermore, automation strategy, safety and easiness of programming was investigated. Results show that collaborative robots have great potential in the middle product volume area. A lot of time, layout space and money could be saved with these solutions. However, standards and safety has to be investigated further in order to reach its fully potential. (C) 2016 The Authors. Published by Elsevier B.V.