Fabrication additive de pièces en polymères thermoplastiques hautes performances et en polyamide 12 par le procédé de frittage sélectif par laser

摘要

Selective Laser Sintering (SLS) of thermoplastic polymer powders is now widely used as a additive manufacturing technique. Nevertheless, this process is industrially mature for only one family of polymers : the polyamides. To use this process in manufacturing applications that are used above 50 °C, it is necessary to increase the range of useable powders to high temperature resistant families of thermoplastic such as poly(aryl-ether-ketone) or poly(aryl-imide). This study investigates the layer-by-layer additive manufacturing of complex parts by SLS from high temperature resistant thermoplastic powders. Seven polymers powders were selected to study their influences on the process steps and the quality of sintered/melted materials. To do so, morphology of theirs particles, microstructures or tapped and poured density are analysed, and also theirs thermal stabilities, capacities to absorb water or theirs flow abilities. In a second step, a study of the influence of process parameters has been carried out to obtain parts with good material quality, taking into account the evolution of the powder after each cycle of fabrication. Moreover, it is important to use all the possibilities of this process in terms of geometry. That is why a law for the mechanical behaviour of laser sintered polyamide 12 has been determined and implemented in a finite element code (ZeBuLoN®). This law, in its linear and non-linear domain, is representative of the material anisotropy and has been experimentally validated on tensile samples and one aerospace part.