Crystallography & Novel Materials

Relatively new manufacturing processes such as 3D printing or additive manufacturing impose a set of thermos-mechanical infl uences on materials. Th ese infl uences have neither been extensively studied nor reported in the literature. For high temperature semi-crystalline thermoplastic materials like PEEK (poly-ether-ether-ketone) these infl uences can be quite pronounced. Th e 3D printing of PEEK requires a strict defi nition of the processing conditions and parameters. One of the challenging aspects of the processing is the control of the temperature profi le dominant in and around the printed part. Th is is especially important because the development of the crystalline phase in 3D printed PEEK part depends on the cooling rate of the melt during the printing process. A typical attribute of 3D printed parts is the structural discontinuities observable on the surface and in the vicinity of the deposited layers. To improve on the structural integrity of the printed part, some heat treatment is conducted on the part. In the current presentation, results for tempered 3D printed PEEK parts are presented. Th e mechanical properties as well as the microstructural state of the PEEK parts are reported and explained within the context of the tempering process.