Effect of Span-80 to Moisture Resistance of Near-infrared Curing 3D Printing Sodium Silicate Foundry Sands

Abstract

In this work, a new method of near-infrared curing 3D printing sodium silicate sands (NIRC3DPSSS) driven by photovoltaic cells was proposed, and the Span-80 moisture resistance modifier was studied. NIRC3DPSSS had the advantages of high strength, rapid curing and low residual strength. However, the 24h storage strength would reduce because Na+ in the bonding bridges could absorb moisture. The experimental results showed that the strength of Span-80 modified sands molds reached 0.95MPa after 4 hours in a humidistat with 99%RH (relative humidity) containing 2.2% sodium silicate, an increase of 97.9% comparing to common sands molds. In air(80%RH), the strength reached 1.25MPa, an increase of 40.4%. The optimal effect of modification was achieved when Span-80 was 0.066% of the raw sands. Additionally, the bonding film and bridges in sodium silicate sands modified with Span-80 were more stable, smoother and free of cracks when observed using scanning electron microscopy (SEM) and energy dispersive spectroscopy(EDS).

Keywords

• sodium silicate sands
• span-80
• near-infrared curing 3d printing
• moisture resistance