Additive manufacturing of small geometrical structures - An analysis of the potential regarding the laser sintering process of a high temperature resistant thermoplastic

Additive manufacturing already addresses the sub millimeter region of small geometrical parts. Regarding laser sintering of polymers with small structures a basic restriction which is often named is the average particle size of the used powder material. But also material properties and the used system technology determine the limits of small geometrical structures. These restrictions often decide about the feasibility of a given task. In this paper the influence of material properties and system parameters are investigated and strategies for optimizing the quality of small geometrical part features are proposed. As an example of a material with a high temperature resistance above 200 °C, tensile strengths above 50 N/mm² and high durabilities of functional parts the high performance polymer polyetheretherketone (PEEK) is chosen. The investigations include the manufacturing of thin single layers perpendicular to the building direction, small pins parallel to the building direction, thin walls manufactured by single laser lines in each building layer and cylindrical cavities as well as vertical inner geometrical features. For these structures the minimum achievable sizes are presented in this paper and an outlook on the potential of the process for manufacturing even smaller structures is given.