Veröffentlichungen

Among engineering materials today continuous fiber reinforced polymers (FRP) show some of the highest stiffness and strength to weight ratios. To rival the traditional manufacturing methods of continuous FRP many investigations have sought to combine the outstanding mechanical performances of these materials with the freedom in design and the economic benefits of additive manufacturing (AM). This paper focuses on the fiber placement strategies and their interaction with Selective Laser Sintering (SLS) specific machine features. The goal is to develop and conduct test series to gain a deeper understanding of how the process, the polymer, and the reinforcement fibers interact. For this investigation different patterns of glass fiber rovings are embedded into specimens made from PA 12 on a Sintratec Kit printer. The rovings are put up onto a frame in varying patterns to be able to relate fiber tension and curvature as well as the stack height of intersecting rovings to the quality of embedding. Additionally the time of placement, the clamping and the interaction of the fibers with the recoater have been investigated. Based on these results an SLS printer with automated continuous fiber implementation will be developed in the future.

Additive Fertigungsverfahren erlauben ohne die Grenzen herkömmlicher Werkzeuge eine nahezu unbegrenzte Designfreiheit. Zur Steigerung von Produktlebenszyklen werden bereits Hybridisierungskonzepte durch Integration von Verstärkungsfasern erforscht. Im vorgestellten Forschungsprojekt wird eine Prototypenanlage entwickelt, mit der sich Endlosfasern in das selektive Lasersintern (SLS) von Kunststoffbauteilen automatisiert integrieren lassen.

Today among engineering materials, continuous fibre reinforced polymers (CFRP) show high stiffness and strength to weight ratios. To rival the traditional manufacturing methods of CFRP, many investigations have sought to combine the outstanding mechanical performances of these materials with the freedom in design and the economic benefits of additive manufacturing (AM). This paper focuses on a novel laser-sintering machine which enables the integration of continuous fibres into the laser-sintering process as well as the identification of influencing parameters for this new process. Firstly, the principle of fibre roving integration is presented. With the help of a heated nozzle, the already sintered layers are melted. A simultaneous motion sequence between the nozzle and the fibre feed is used to insert the fibre into the molten material. Secondly, machine- and process-related parameters are identified which have an influence on the fibre integration. By using an influence analysis, the parameters will be investigated and parameter sets for a successful fibre integration will be found. The identified parameters are to be used for future investigations. The results of this paper show the potential of continuous fibre integration in the laser-sintering process based on measured tensile properties.