Impact of binder jetting process parameters on sand mould friability

The growing application of the binder jetting process for the manufacturing of sand moulds, beyond prototyping, has highlighted the need to understand the effects of process parameters on mould properties. Friability is a crucial foundry property of moulds, related to the resistance of mould erosion during the pouring of liquid metal. In this study, test samples were printed using the Voxeljet VX1000 system and evaluated for friability, with results ranging between 11% and 44%. Artificial Neural Network (ANN) modelling and sensitivity analysis were employed to identify key process parameters affecting friability. AFS (American Foundry Society) grain size emerged as the dominant factor, accounting for 80% of the total impact. Coarser grains significantly improved mould durability by enhancing particle packing and bonding strength. Drop mass (resin concentration) ranked second with a 12% impact, while printhead speed followed closely at 11%. DX (print resolution) exhibited the lowest influence at 6%, indicating that while the distance between drops of binder remains essential for structural integrity, it is not the primary driver of friability. This study is in line with South Africa’s strategy for the implementation of additive manufacturing in the foundry industry.