The castings necessarily require final machining as they present casting imperfections. This master's thesis deals with designing a method for extracting the polymeric model in sand molds to optimize the time and surface finish in aluminum castings, avoiding final machining. The study was developed using an applied methodology, starting with modeling and 3D printing the polymeric model in PLA material. Then it is placed in the molding box and filled with the sand mixture, and the compact block is inserted into the muffle, up to a temperature of 300℃. Next, the compact block is inserted in the muffle, up to a temperature of 300°C, for 150 minutes, after which the polymeric model disintegrates, leaving the hollow cavity, to pour the molten aluminum at 800°C and let it solidify completely ℃.