Effect of binder saturation and powder layer thickness on the green strength of the binder jet 3D printing (BJ3DP) WC-12%Co powders

Abstract

Printed parts displaying good green/handling strength are vital for the Binder Jet 3D Printing (BJ3DP) process to succeed in manufacturing complex parts with thin sections and tiny intricate features. A study was carried out to understand the effect of the binder saturation and powder layer thickness on green strength of the printed samples. The ability of using the green strength data of the samples to identify the optimum processing conditions for printing was examined. The strength of the parts were evaluated after printing at binder saturation levels of 45–75% and powder layer thickness of 50-70 μm. For any given powder layer thickness, the strength of the samples increased with increase in binder saturation. The samples printed at 60 and 75% saturation showed similar strengths at 50 and 60 μm layer thickness. However, the strength decreased with further increase in powder layer thickness to 70 μm. Doubling the binder set time and increasing the binder saturation options were evaluated to minimize the difference in the strength of the parts printed at 60 and 70 μm thickness. Increasing the binder saturation was found beneficial in minimizing the difference in the strength of the parts printed at 60 and 70 μm thickness compared to doubling the binder set time.