Deformation study of ceramic mold with complex structure by dimensional measurement of Sn-Bi casting

Abstract

Sn-Bi alloy casting measurement method was used to measure the inner cavity dimensions of molds with unconstrained/constrained structure features. All the external diameters expand, and the inner diameter shrinks after the dewaxing process. As the expansion rate of the inner cavity with thinner thickness is more sensitive to the expansion value, the expansion rate decreases with the increase of the cavity thickness. Compared to the mold dimensions after dewaxing, all the diameters of the fired molds become greater. With the rise of firing temperature, the expansion rate of the mold diameters tends to decrease. The inner diameter has a much lower expansion rate than all the external diameter at a certain temperature. For the uneven radiation heat transfer of the furnace and the complex structure of the mold, the temperature field of the mold is unevenly distributed in firing process. Under the influence of constrained structure, microscopic cracks appear in mold to relieve the unsynchronized deformation, which will cause the expansion of the mold.