Today the global market poses great challenges for the industrial product development. Complexity, diversity of variants, flexibility and individuality are only some of the features the products have to fulfil today. Additionally the product series have shorter and shorter life times. Because of their high capacity for adaption, polymers are increasingly able to substitute traditional materials such as wood, glass and metals out of various fields of application. But the polymers are only able to substitute other materials, if they are optimally suited for the specific applications. So a product specific material development is more and more important. The problem is that the traditional development process for new polymer formulations is much too complex, too slow and therefore too expensive. So a product specific material development is out of the question for most of the processors. The integration of the compounding step into the injection moulding process would lead to a more efficient and faster development process of a new polymer formulation which results in the opportunity to create new product-specific materials. This process is called inline-compounding on an injection moulding machine. In order to develop this innovative formulation development (with the focus on fibre reinforced thermoplastics), different screw-concepts are compared concerning to the resulted performance characteristics, such as mechanical properties and fibre length distributions. Furthermore the fibre damage along the plastification unit was investigated with the help of dead-stop-experiments.