Continuous Orbital Winding of Thermoplastic FRPs

Today’s markets are characterized by a strong need for automation in the thermoplastic FRP component production. Therefore, as part of the federal excellence cluster “MERGE multifunctional lightweight structures” the development of a novel processing method was realized, which is a synthesis of thermoplastic tape winding and automated tape placement technology. The new continuous orbital winding (COW) process, based on a modular technology concept with various processing units, enables the production of closed structural components and allows the direct combination with upstream and downstream processes. Hence a value chain improvement can be reached. That is achieved by linear motion of the winding mandrel (e.g. thermoplastic liner) along its longitudinal axis through the rotating winding units. The winding units coat the liner with unidirectional reinforced thermoplastic semi-finished structures by the use of tape placement devices. The applied thermoplastic tape welding process merges the matrix material of the incoming thermoplastic tape and the one of the previous layers.

This paper is presenting the validation of the manufacturing process of closed structural rotational and non-rotationally symmetric component using unidirectional fiber reinforced tapes, with the pilot plant for COW technology. In the first step of implementing a new part, the dataset of the part model is converted into a triangulated surface model in .stl file format. Following, the model can be imported into a Mathcad® file to project the winding pathway on the surface. These trajectories are used to calculate and determine the drive parameters by an inverse kinematic algorithm. Subsequently, the pilot plant can wind the profile with the computed contour. The final evaluation of the welding quality is necessary for the validation of the manufacturing process.

Keywords:Fiber reinforced thermoplastic tape; Winding process; Tape placement; Orbital winding/wrapping process; Mass production process; Automatic trajectory generation