The effect of ageing process on three-point bending strength and permeability of 3D printed sand molds

The objective of this paper was to investigate the effects of curing parameters (i.e., temperature and time), on the permeability and mechanical strength of the printed molds. Several sets of samples were hence produced with a state-of-the-art 3D printer using well-characterized silica sand and furan resin binder. Then, experiments were performed in which the evolution over time of the three-point bending (3 PB) strength and permeability of the samples were monitored at three different curing temperatures. From these measurements, both the individual and combined effects of curing temperature and time on the functionality of the 3D printed molds were assessed. Moreover, loss-on-ignition (LOI) tests were also performed in order to relate the loss of binder mass to the variation in permeability and mechanical strength of the samples. The results showed that the printed molds can be stored at room temperature for a long time before being used, roughly preserving the initial properties. No significant change in 3 PB strength was observed when curing at 100 °C. In contrast, the permeability was shown to decrease with increasing curing temperature.