Abstract
This research study investigates the possibility of mechanically reclaiming the waste sand gen-erated during the printing of sand cores using the Voxeljet VX1000 printer. During the printing of sand cores using the Voxeljet VX1000 printer, an appreciable quantity of waste sand is generated. In line with environmental regulations and taking the increasing cost of sand into consideration, it has become imperative to consider implementing the recycling of waste sand in the rapid sand-casting process. This dissertation provides research into sand reclamation in the field of three-dimensional printing.
In this study, two types of waste furan-bonded sand generated from three-dimensional printing using the Voxeljet VX 1000 printer were collected from the Vaal University of Technology. The sands were first characterized before being mechanically reclaimed using dry and wet at-trition. The dry attrition involved dry milling the waste sand followed by dry screening. The wet attrition involved washing the waste sand in a liquid solution consisting of water and iso-propyl alcohol.
From the results obtained, a slight drop in the sand’s AFS or Average Fineness number after mechanical reclamation by both dry and wet attrition was observed. Waste sand 1 showed an initial AFS of 80.35 which dropped to 79.73 after dry attrition and 78.04 after wet attrition. Waste sand 2 on the other hand started with an AFS of 68.05 which dropped to 64.25 after dry attrition and 63.78 after wet attrition. The reclaimed sand maintained a pH of 3.8–4.4 after dry attrition and 6.8–7.3 after wet attrition, making the sand slightly neutral. The loss on ignition results after mechanical reclamation by wet attrition showed a drastic decline. For instance, Waste sand 1 had an initial loss on ignition content of 0.54 percent which dropped to 0.52 percent after dry attrition and 0.31 percent after wet attrition, Waste sand 2 showed a similar trend. The sands’ pH and loss on ignition results demonstrated that mechanical reclamation using wet attrition is more effective in removing the residual binder in the sand than mechanical reclamation using dry attrition.
Keywords: Three-dimensional printing, Voxeljet VX1000 printer, furan resin, waste sand, me-chanical reclamation, wet attrition, dry attrition.