Diseño de molde para procesos de inyección de plástico y fabricación de sus placas de núcleo y cavidad de manera didáctica

Abstract

When designing a mold for a part manufactured by injection molding, it is essential to focus on producing parts in cycles with relatively short time spans, they must fulfill the function for which they will be manufactured, the quality, the cost and seeking to reduce the waste of resources in the process, for this reason, carrying out the design, manufacturing and validation process of an injection mold requires responsibility, knowledge and commitment on the part of the engineer, who must clearly understand the previously stated requirements [1]. It is essential to rely on the existing computer-aided design technologies or tools (CAD/CAM/CAE), which allow the design and development of components, so it is necessary to have the skills and abilities to use this type of technology and thus provide optimal solutions. When executing this project, a series of steps were observed that are required for the design and manufacture of a prototype injection mold, for this this research was mainly divided into seven stages. The first phase basically consists of identifying the manufacturing needs of the part, examining first of all what tools the machining center located in the faculty facilities is equipped with and thus identifying the complexities, limitations and scopes in order to know the ideal working parameters of the equipment and finally to define the geometry of the part. In the second stage, the simulation of the process was carried out with the help of CAE tools (MoldFlow Adviser), in addition, the theoretical corroboration of the parameters of a complete injection cycle was carried out supported by documentation from injection machinery manufacturers and documentation from research and academic works in order to size the required equipment, in this way making a comparison guaranteeing that what is shown in the simulated analyses is as close to reality as possible with the data obtained theoretically.

In the third stage, on the other hand, the dimensions and geometries that govern the injection mold are established. 3D models of the cavity and insert plates, clamping and ejector plates, feed and cooling channels, ejection mechanisms, sprue and other components that make up the total assembly of the mold are obtained. In addition, the plans for each of them are drawn up, which will facilitate their understanding and operation. Once the 3D models of the mold components have been defined, the fourth stage of the project begins, in which the conditions are established and the trajectories for the machining operations that will be carried out for the manufacture of the core and insert plates of the mold are developed. The paths that the tools will take are simulated and corroborated to obtain the desired geometries in order to avoid future damage to the material at the time of machining and finally the NC codes necessary for the manufacturing practice of the plates are obtained. In the fifth stage, the manufacturing phase was executed with the help of CAM tools and was materialized with the equipment with which the faculty is equipped, specifically with the CNC machining center. The final product is a manipulable prototype of the cavity and core plates of the mold for injection processes, as well as the files to view in a virtual environment the rest of the components that intervene in the process and together, ensure optimal performance. The sixth stage is based on the financial evaluation which consists of a calculation of costs of materials, labor and equipment, as well as an estimate of the machining times to execute the manufacture of the components that make up the injection mold object of study of this project, and thus, give it a more industrial approach. The results obtained will serve as a basis for making informed decisions about the investment in the injection mold, the economic viability and its impact on future production processes. The culmination of this project comes hand in hand with the seventh stage, here the focus is on the materialization, elaboration and socialization of the technical document that details the investigative and practical process carried out, from the conceptual design to the manufacture of the core plates and insert of the mold. This document not only serves as a historical record of the project, but also constitutes a valuable tool for future references, allowing for process replication, design optimization, and resolution of possible incidents in injection cycle processes.