Uma contribuição ao processo de rotomoldagem em polietileno

Abstract

Rotomolding is the polymer transformation process that currently has the greatest growth space in the industry, however it is still a process that needs studies for its improvement. Technical knowledge is poorly parameterized for this process, resulting in the application of the empirical method to solve various problems and also to improve current techniques. The main advantage of rotational molding is the ability to produce parts without residual stresses, resulting in parts with high impact resistance. The main disadvantage of this process is the high cycle time, and most of the research in the industry is for the reduction of time in the process. a piece that can have large dimensions and weight. Considering this difficulty, a reduced-scale laboratory equipment was built, making it possible to carry out comparative experiments, bringing parameters that can be extrapolated for application in the product’s real scale. Rotomolding molds basically have two types of internal finishing, polished and shot-peened. With two molds, each with these respective finishing, the possibility of difference in processing time between them, due to the difference in internal roughness, was investigated. In this study, it was possible to evaluate the behavior of the rotational molding process and compare, through the analysis of the mold’s internal temperature, the thermal behavior in molds with these two types of surface finishing. The results showed that there is a difference in the behavior of the temperature curve inside the mold, but there is also similarity at a certain point in the process, depending on the stage it is in, showing that the blasted mold requires less processing time. The study also brought understanding about the way that heat acts during the mold heating and cooling process.