SUNConferences, 17th Annual Conference of the Rapid Product Development Association of South Africa

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Suitability of South African silica sands for the Three Dimensional Printing of foundry moulds and cores
Oyombo dady, Kasongo nyembwe, deon de beer

Last modified: 2016-10-03

Abstract


Applications of Three Dimensional Printing (3DP) to Metal Casting include, among others, the direct manufacturing of foundry moulds and cores in refractory materials such as silica sand. The main properties of silica sand essentially related to the traditional moulding and core-making processes are: size distribution, clay content, pH, acid demand and refractoriness. In addition to these properties, the silica sand used for 3DP must be appropriately selected for the layer-based manufacturing process involved in 3DP. Properties such as size distribution, grain surface morphology, angularity, free-flowing and re-coating abilities have a particular importance when determining sand suitability. Because of these extra requirements, only a limited amount of foundry silica sands available can be used for 3DP processes. The latter situation explains the scarcity and expense of suitable silica sands, thus contributing to the relatively high operational costs of the 3DP processes for the production of sand moulds and cores. This research paper will investigate the suitability of local silica sands for their use in 3DP processes. A two-step methodology will be adopted, consisting firstly of the reverse–engineering of a silica sand utilized in the 3DP process available in South Africa to determine its properties. The characterization study will then be followed by the comparison between the properties of the selected 3DP silica sand and those of the local foundry sands whose properties were recently determined by the National Foundry Network sand profiling study. A subset of potential local sands, fit for additive manufacturing, will then be identified for further performance assessment on 3DP machines.