Influência do ciclo de resfriamento do molde na obtenção de discos cerâmicos por injeção em baixa pressão

Abstract

This research presents a study which has been developed to identify the influence of cooling cycle on ceramic pieces produced by the process of injection molding of ceramics in low-pressure. For the tests two types of discs using a ceramic suspension with 86 wt% of alumina (Al2O3) and 14 wt% of organic vehicle were produced. A disk with dimensions of Ø80,00 x 3,00 mm has been used as an experimental part for dimensional analysis (shrinkage) and geometric analysis (flatness and roundness). Another disc with dimensions of Ø23,86 x 1,79 mm was utilized for measuring density and flexural strength by biaxial method in a ball on three balls. Three cooling conditions were used in the mold for the manufacture of ceramic disc: low rate of cooling, high cooling rate (both initiated after injection of ceramic suspension) and continuous cooling during the injection cycle. The analyses showed that the high rate of cooling had the highest flexural strength but high dispersion in the results. The condition with low cooling rate obtained higher dimensional shrinkage, higher flatness deviation and a lower flexural strength, but with less variation. Using continuous cooling the samples showed a density with lower variation, but the samples had low shrinkage due to higher compression molding of ceramic suspension.