Abstract : The effects of resin infusion process parameters on the mechanical properties of stitched or non-stitched composite laminates out of autoclave were studied using the design of experiment method. This method was chosen due to the complexity of the problem. The preforms used were laminates of multi-axial quasi-isotropic non-crimp fabric (NCF), either stitched or non-stitched. A literature review identified nine parameters as the key design-of-experiment factors: sewing; the number of NCFs; the number of high-porous media; the interaction between the number of NCFs and the number of high-porous media; the mould temperature, injection temperature and cure temperature; the position of the preform; and, finally, the vacuum level. The mechanical properties studied and the morphological analysis carried out concerned the resistance in tension, compression and shear, the glass transition temperature, the thickness of the finished laminate, and the fibre volume fraction and porosity. The study revealed the best suited manufacturing conditions.
