Additive manufacturing (AM) of polymer large parts is a technological research area with great growth potential if the main barriers to its implementation are successfully addressed. In this research, a review of large-format AM (LFAM) processes for polymers is presented, followed by market research concerning the identification of large-format polymer commercial printers. An overview was performed covering the current LFAM systems configurations and their control aspects. The design and modelling approaches related with the fabrication of polymer large parts by AM, and the materials currently being applied and under development, were described. Finally, a summary of LFAM applications with a focus in the Transportation, Academic, Construction and Energy sectors, was presented. The current main advances in the LFAM of polymers are linked with the possibility of producing large parts in a faster, cheaper, and reliable way. The market research analysis concerning results for all AM families involving polymer materials reveals that, currently, the material extrusion AM process family is potentially the most suitable to produce large parts, with a significant number of applications attesting its capability to produce such large-format components.

This work aims to study the influence of protective coatings on the water absorption and mechanical properties of 3D printed poly–lactic acid (PLA) parts. The PLA parts were fabricated with different levels of the 3D printing process parameters, aiming to define samples with distinct strength and ductility/toughness characteristics. Water absorption tests following the standard ASTM D570–98 were performed on uncoated and coated PLA specimens. The effectiveness of two protective coatings based on acrylic and polyurethane varnish on reducing water absorption was evaluated. Both protective coatings have shown being effective on preventing water absorption by the PLA, with polyurethane presenting the best performance reducing water absorption by 38%. Tensile tests were carried out to determine the ultimate tensile strength, elastic modulus, yield tensile strength, fracture strain and toughness of specimens, before and after the application of protective coatings. The polyurethane protective coating also benefits the tensile properties of PLA parts, increasing the strength and ductility/toughness characteristics of specimens up to 24%.

The applicably of multi-objective optimization to ellipsometric data analysis is presented and a method to handle complex ellipsometric problems such as multi sample or multi angle analysis using multi-objective optimization is described. The performance of a multi-objective genetic algorithm (MOGA) is tested against a single objective common genetic algorithm (CGA). The procedure is applied to the characterization (refractive index and thickness) of planar waveguides intended for the production of optical components prepared sol-gel derived organic-inorganic hybrids, so-called di-ureasils, modified with zirconium tetrapropoxide, Zr(OPrⁿ)₄ deposited on silica on silicon substrates. The results show that for the same initial conditions, MOGA performs better than the CGA, showing a higher success rate in the task of finding the best final solution.