Impact of different annealing methods on MEX‑printed polyetherketoneketone parts

Material extrusion is an established category of additive manufacturing, primarily using thermoplastic materials for product development. The continuous quest for improved material properties and superior surface finish has driven significant interest in the development and application of advanced post-processing techniques. In this work, Antero 800NA has been used, which is a Polyetherketoneketone thermoplastic of the polyaryletherketone family, with excellent mechanical and thermal properties as well as high chemical resistance. To enhance the performance of Antero 800NA parts, three annealing methods were used in this work. They include oven annealing, fluidised bed annealing, and metal plate annealing. Temperatures of 160 °C, 180 °C, and 200 °C were used for three different time intervals of 1, 2, and 3 h. Metal plate annealing showed overall better dimensional integrity and surface finish compared to oven and sand annealing. However, sand annealing showed reduced dimensional variations at the 2-h annealing time-interval for all three temperatures. Tensile testing showed varying results with sand annealing, oven annealing, and metal plate annealing showing higher tensile strength at 160 °C, 180 °C, and 200 °C, respectively. Microstructural analysis showed a compact and cohesive structure with finer microvoids for high tensile strength specimens and larger voids as well as delamination for low tensile strength Antero 800NA specimens. Metal plate annealing also demonstrated higher hardness values, whereas oven and sand annealing showed consistent but lower values compared to metal plate annealing. These results provide a comprehensive comparison of three distinct annealing methods for Antero 800NA parts that can offer valuable insights into optimising post-processing techniques for engineering applications requiring enhanced performance of additive manufactured Antero 800NA parts.