Abstract
Rapid sand casting processes by additive manufacturing are predominantly based on furfuryl
alcohol resin bonded sand catalysed with sulfonic acid. The prior coating of the refractory
sand with sulfonic acid is a crucial process to ensure the suitability of the sand for threedimensional
printing applications. The present paper investigated the sulfonic acid coating
process of a local silica sand, which was found to have potential for three-dimensional
printing applications in previous studies. Experimental conditions included sulfonic acid
catalyst addition and mixing time. Coated sand was assessed for flowability and mechanical
properties of test specimens produced by three-dimensional printing using a Voxeljet VX
1000. The optimum catalyst addition ranged between 0.3 and 0.6% yielding to transverse
strength in the order of 110 to 165 KN/m2 and tensile strength ranging from 710 to 770 KN/m2.