Stereolithography for the fabrication of ceramic three-dimensional parts

Ceramic three-dimensional parts can be produced by a stereolithography (SL) process using a ceramic suspension containing alumina powder, UV curable monomer, diluent, photoinitiator and dispersant. The monomer reacts to UV radiation (argon ionized laser) and is transformed into a solid polymer which is then removed by thermal treatment (debinding). Subsequent sintering of green parts leads to dense ceramic parts. The effect of each component on the rheology of the alumina suspensions has been studied first. Both the addition of dispersant and diluent and the increase in temperature allow a significant decrease of the viscosity of the suspensions. The highly loaded (more than 55 vol. per cent), homogeneous and stable suspensions have a shear thinning behaviour which is favourable for casting the layers. Adequate cured depth (above 200 mu m) and satisfactory transversal resolution have been obtained and these allow the production of ceramic parts, which demonstrates the feasibility of the process. Sintering at 1,580 degrees C leads to dense ceramic parts with homogeneous microstructure. The process still needs to be optimized to further improve the mechanical properties.