Role of Mixing Method and Solid Content on Printability of Alumina Inks for Stereolithography 3D Printing Process

Abstract

Additive manufacturing of ceramics via stereolithography method is a promising way to fabricate high-resolution ceramic parts with complex geometry, which is hard to obtain with traditional ceramic shaping methods. In order to shape the ceramics with the Digital Light Processing (DLP), a mixture of photocurable resin and ceramic powders, called ink, must be prepared. In this paper, the printability of the Alumina-glass inks, with different solid contents were prepared by two mixing methods, having long and short mixing durations. In order to evaluate the printability of inks, the rheological behavior of suspensions was investigated, and printing parameters such as curing time and layer thickness were changed. The ceramic-resin suspensions were prepared via 24-hour ball-milling and 10,000 rpm mechanical homogenizing. The suspension containing 60 wt% solid content and prepared by mechanical homogenizing showed the best stability with 8% sedimentation within 4 days and the lowest viscosity of 1.37 Pa·s at shear rates of 30 s-1, exhibiting a suitable viscosity for DLP printing. Therefore, a mechanical homogenizer can be a promising and quick method for mixing by providing simultaneously appropriate rheology and printability.