Manufacturing companies are operating today in a turbulent market. Permanently changing preconditions forces the companies to continuously adapt their business and production processes to get the optimal productivity. Therefore, a vast number of IT systems are introduced to support tasks along the product life cycle. These systems are typically isolated and their communication, cooperation and in special cases also integration results in more and more overhead and gets quickly unmanageable. Further problems arise, when building continuous processes within the Product Lifecycle Management (PLM). The service-based PLM architecture faces these challenges and presents a homogeneous integration approach based on Enterprise Service Bus (ESB) technology. The characteristics and findings of our approach are presented and the inclusion of security features is discussed. A proof-of-concept for the production planning and the corresponding Production Planning Service Bus are presented. Finally, the advantages of the service-based approach compared to traditional integration solutions are pointed out.