Many companies have been reorganizing from a sequential to an integrated path known as simultaneous engineering, which aims to reduce development time and costs. The main problem during technology and product development is the integration of the design and manufacturing areas in the product development phase. This paper proposes a model to improve the use of simultaneous engineering by integrating project and manufacturing knowledge areas based on concepts of manufacturing readiness level, design for manufacturing and assembly and technology readiness level. Based on a bibliographic review and a preliminary study conducted over 1 year in a multinational metalworking company, a model was proposed as a method to be applied in the early stages of product development. The results show an integration of proposed engineering areas into a product development process, a cost reduction of 20% and a manufacturing investment reduction of 25%.