Diseño de un método de extracción del modelo polimérico en moldes de arena que permita optimizar el tiempo y acabado superficial en fundiciones de aluminio.

Abstract

The aim of this master's degree work is to design a method of extracting the polymer model in sand molds to optimize the time and surface finish in aluminium castings, avoiding final machining since the pieces melted by traditional methods, necessarily require a final machining because they present imperfections of casting such as, metal projections, cavities, discontinuities, faulty surface, incomplete casting, incorrect dimensions or shapes, inclusions. The study was developed using applied research, so it began with the modeling and 3D printing of a six-helix turbine in polymeric material polylactic acid (PLA), to which an amount of chloroform proportional to its volume of approximately 0.5 mm was applied, to obtain an acceptable result. Then this was introduced and covered with a mixture of silica sand and bentonite in the molding box, once the mixture was dried, the compact block was inserted into the muffle where it was subjected to variable temperatures until reaching 300 ° C, in a time of 150 minutes, temperature at which the polymeric model disintegrated leaving the hollow cavity of the mold. The molten aluminum was poured at 800 ° C allowing to solidify completely, finally the molten turbine was released, after a brief manual cleaning, the surface finish tests were carried out to the specimens. resulting in a roughness of 2.557μm, which is much higher than that obtained with the traditional 9.18μm method, with a significant difference in time spent in the 20.45h process in obtaining the model and with a savings of $235 in the cost of manufacturing between the traditional method and the proposed innovative method.