Determination of process induced dimensional variations of ceramic parts, 3d printed by extrusion of a powder-binder feedstock

This paper aims at presenting a methodology for compensation of dimensional variation during production of ceramic parts via extrusion based additive manufacturing process. A systematic geometric deviation is measured in as printed (green) and as sintered parts. In the present study, a specially developed CNC extrusion unit is used for 3d printing onto a 3 degrees of freedom parallel kinematics table. Two ceramic feedstocks, alumina and zirconia, are procured and their processing route is illustrated. The generated, corrected and modified G codes are directly fed to the controller of the table and extrusion unit. Validation of the performance is carried out by multiple samples and repeated measurements. Experimental results exhibit effective compensation and significant improvement in the dimensional accuracy. The calculation of geometric deviations and the proposed parametric determination through optimization allow the reduction in global dimensional variation, which decreases all sort of systematic errors concurrently. The proposed procedure is easily transferable to other rapid prototyping machines and allows scalability based on achieved surface quality, manufacturing time, mass and dimensional measurement.