The choice of this topic of the final degree project is determined by my passion in the automotive field and modern technologies. Today, modeling objects in 3D printers have become an ordinary practice for some engineers, which is why I was captivated by the idea of being able to merge the world of cars with 3D printing. Throughout this program, the aim is to carry out an extensive documentation on the creation of a speed reducer, which in this case will be a gearbox, to acquire all the necessary capabilities to produce one. In order to provide an understanding of the theoretical work, a reducer will be designed with the Solidworks program. This will then be printed piece-by-piece on a 3D printer and assembled.