One way for firms to stay competitive is to adapt a platform approach. In product platforms, modules are used as exchangeable design blocks to create a variety in product performance. This is a proven way to get advantages of scale in production by reusing physical parts and investments in manufacturing. To ensure exchangeability between modules, interfaces between modules must be well defined. Hence, from this point of view, there is no such thing as flexible modules. In this research, flexibility refers to the idea of identifying strategic portions of the platform where flexibility is needed and to create the modular division in a way that the assigned modules are de-coupled in theses areas. The presented approach shows how the Design platform concept can be extended by the introduction of flexible modules. These support the Design Platforms by allowing areas of strategic importance to be more flexible and thereby enable room for uncertainties such as fluctuating requirements and future technical development.