Modelado 3D y construcción de una matriz de soplado para botellas PET por medio de un equipo CNC para la empresa MOLPLASTIC.

Abstract

In this project, a PET (polyethylene terephthalate) bottle blow mold was manufactured, to obtain the internal cavity of the matrix a profile in revolution was used in order to be able to machine in a CNC (computer numerical control) lathe of the company Molplastic. The mold design, workshop plans, assembly in a CAD program (computer aided design) was obtained, tools of the company were used to obtain the G code, this program must run on the CNC lathe, without errors and thus obtain the internal cavity of the mold. Once the whole model of the die and the machining program were obtained, the manufacturing of the die was started. Starting from duraluminum blocks (7075 aluminum) which were machined by chip removal processes, in conventional machines such as lathe and milling machine, with which parallel and perpendicular faces with a fine surface finish were obtained. Subsequently, holes were drilled to place pins and bushings that helped to assemble the two blocks that make up the matrix in order to be able to hold them on the CNC lathe. The duraluminum blocks (7075 aluminum) placed on the lathe were centered with the help of a dial indicator and started by passing drills in order to remove the largest amount of material to later run the program and thus the internal cavity of the mold was obtained. In addition, the CNC lathe was used to manufacture all the elements of revolution such as pins, bushings and the base of the mold. Next, the internal cavity of the mold and the mold base were polished. Finally, it was assembled and blowing tests were carried out in order to compare the bottle obtained in the tests with the 3D model. With this methodology, it was concluded that it is possible to obtain a blow mold by means of a CNC lathe, instead of using a machining center, which is a more expensive equipment and to which in many occasions there is no access.