Heat treatments for improved quality binder jetted molds for casting aluminum alloys

Abstract

The objective of this paper was to investigate the most suitable heat treatment for casting molds manufactured by binder jetting. For this purpose, the printed molds were subjected to different heat treatments and the properties of the molds were analyzed. Tests were performed at different temperatures and times to investigate their effect on the water and volatile substances content; the joining among particles; and the porosity, roughness, and compression strength of the printed molds. Moreover, to relate the properties of the mold with the quality of the castings, aluminum alloy specimens were cast and the dimensional accuracy, surface roughness, mechanical strength, and porosity were evaluated. This research leads to the conclusion that the binder jetting process, using calcium sulfate powder, is useful for manufacturing molds for casting aluminum alloy. To improve the mold quality and, consequently, the casting quality, heat-treatment is necessary. The best mold properties were obtained at 250 °C for 1.5 h.