It is well known that industry is suffering a transformation called industry 4.0, occurring in the majority of developed countries where the use of a number of disruptive technologies are increasing efficiency and effectiveness of processes aiming the boost of competitiveness. Additive manufacturing is one of the technologies that builds this new industrial paradigm; and product design and development evolves by the use of these emerging processes defining new product categories and new business models, within the context of mass customization. In this article, we will describe the process of design and development of a consumer product, an electric guitar, through an additive manufacturing technology: fused deposited modeling of semi-molten polymers. Illustrating the design and development stages and tools for the product to be adapted to the possibilities that this additive technologies offer in terms of flexibility and geometric complexity adapting the geometry of every product to the ergonomics needs of every user in a fully automatic process. Key words: Additive manufacturing, Industry 4.0, mass customization, fused deposition modeling, parametric design, industrial design, CAD computer aided design, Electric guitar, user centered design, product ergonomics.