Inside Hybridization of CF/PAEK Hollow Profiles by Means of Injection Molding

Hollow profiles made of braided thermoplastic tape material are able to meet the demands of future aviation applications in terms of cost, cycle time and mechanical properties of structural components. By using the overmolding technology additional elements, i.e. load introductions, can be formed onto the hollow profile, increasing its functionality. This work presents a novel processing route for a driveshaft load introduction design of hollow profiles, whereby the load introduction element is injection molded onto the inside of a thermoplastic hollow profile. To form the contour of a splined shaft of the injection molding part inside the hollow profile, a collapsible core is used in conjunction with a ring gate. In order to ensure a proper bonding between the injection molding material and the composite, the hollow profile is heated externally in an infrared oven and then transferred into an injection molding tool for the functionalization step. This process set up requires a precise adjustment of the wall thickness of the hollow profile, the contour of the collapsible core and the process temperature. Extensive processing trials are performed on different temperatures and laminate configurations. Photomicrographs, computer tomography scans and mechanical tests are used for evaluating the part quality.