Projeto e Simulação da Automação por Linguagem Ladder® de Máquinas Injetoras de Plástico

Abstract

Plastic injection molding is a versatile and efficient manufacturing process, being the second most used process for manufacturing of plastic products in Brazil during the year of 2021. In the plastic injection molding process, the molding material is melted through friction between the screw and the heated walls of the injection cylinder, and is then injected under pressure in the mold cavity, following a period of cooling, the final product is ejected from the mold automatically, and the process can then be repeated immediately. The injection molding process allows mass production of articles of varying dimensions and geometry. The present work has as objective to develop the project and simulation of automation of a plastic injection molding machine using programmable logic controllers. The simulation of the hydraulic- pneumatic-electrical circuit of the machine was developed using the software FluidSim®, and based on the result, the ladder program for the circuit was created. Subsequently, the project was simulated on a test bench with a relay circuit, and later, with a Festo® Compact PLC. The use of ladder logic demonstrated advantages by allowing the use of internal relays that greatly simplified the assembly of the physical circuit, as well as the ease of implementing changes on the system by simply modifying the ladder code. The simulation enabled the acquisition of knowledge relevant to PLC automation using ladder logic. Keywords: Industrial automation, plastic injection molding, ladder logic, programable logic controllers.