Additive manufacturing is an emerging disruptive 3D printing technology that is stimulating innovations in design and engineering, materials, and manufacturing thanks to the prospects of reducing cost and waste and increasing efficiency; in doing so, it presents the potential to have marked industrial, economic, and societal impacts. Thermoplastic polymers show some ideal characteristics for the most common additive manufacturing methods, and this aids in the improvement of the design accuracy and reliability and makes inroads for the customized manufacturing of high-design-flexibility polymer parts. Despite this, this material family is strongly sensitive to temperature, and one of the viable ways of limiting this weak point is surface coating with thermal barriers. The focus of this work was the optimization of an additive manufacturing process for producing thermoplastic components and to improve the adhesion of a thermal barrier coating on their surface. In detail, flat plate specimens of ULTEM 1010 were obtained by the fused deposition modeling technique by varying two significant surface parameters, the enhanced visible rasters and the visible raster air gap; then, their surfaces were covered by a thin ceramic coating by an air plasma spray system. A micro-geometric analysis that was conducted using a confocal microscope and the coating thickness measurements highlighted that a global larger roughness value, the presence of more flat peaks with a large area, and the complexity of the texture can be considered as supporting factors for improving the mechanical gripping and allowing a uniform adhesion of the coating powders on the thermoplastic substrate.