Reduction of Dewaxing and Sintering Time by Controlling the Particle Size of YSZ Particles for Stereolithography

Abstract

In ceramic stereolithography, composite “green” bodies must be thermally processed to de-bind organic content and sinter the material. The conventional process for dewaxing and sintering of yttria stabilized zirconia stereolithography components is typically very long. The time and energy cost of thermal treatment of these components can be reduced by controlling the size of the solid particles in the photosensitive material. The Discrete Element Method was used to model the number of particle contacts per mass using particles of various median diameter, and a three-dimensional curved surface graph was generated. Ceramic slurries were prepared using powders that fulfilled the conditions of various calculated data points from the DEM model analysis. The prepared slurries were processed by stereolithography additive manufacturing and fabricated precursors were thermally processed to dewax and sinter the parts. The relationship between the particle size and the occurrence of crack formation after heat treatment was investigated. Heat treatment parameters were further investigated using the predicted slurry composition that was optimal for crack prevention. The required time for dewaxing and sintering of yttria stabilized zirconia components was reduced to one tenth of the conventional time through optimization of slurry composition and thermal treatment schedule.