The primary target of this project consists of combining the technique of rapid prototyping and casting to produce aluminum parts in a sand mold being made the corresponding models and core boxes by means of the technology of rapid tooling, FDM (fused deposition modeling) of ABS. The followed process to obtain the pieces is casting, that consists of the fused metal spill in a mold pattern previously conformed, followed of a cooling and later rinding of the solidified piece. The models and core box, generally, is made in wood or plaster, but in this case they were made by means of a Rapid prototyping machine of the company 3Ddimension. The phase of design and manufacture of the model and the mold are most expensive and critical of the process. In this work it is tried to study the valuation of the time of manufacture of the models, core box and molds. The application Catia V5 R17 has been used for the geometric definition of the model and care box. This model is exported in stereolithography format (stl) and after this, the file was sent to the printer Dimension BST 768 and begin the construction of the models. The proposal methodology using rapid prototyping to generate the models is a clean and fast solution, and in addition it allows to obtain geometries that are nonviable by another procedure. The surface finish quality of the model is appropriate for the casting process, and reproduces with a high reliability the model CAD.