Abstract
Successful case studies of metal casting applications using sand moulds and cores produced by additive manufacturing (AM) processes have been widely reported in the literature. The layered- based manufacturing process has revolutionised traditional sand moulding methods. This is essentially due to the numerous advantages of AM, including the reduction of design lead time and the ability to manufacture objects with complex geometry in a rapid turnaround time. Locally-available AM processes that are capable of producing sand moulds and cores include laser sintering (LS) and three-dimensional printing (3DP), with the latter AM process growing in dominance over the former. However, a better understanding of the properties of parts produced by AM processes is required in order for the processes to be fully adopted by the foundry industry. Crucial characteristics of 3DP sand parts related to strength, dimensional accuracy, and hardness are not well- known in terms of their magnitude and in comparison with conventionally-moulded sand parts. In this investigation, the physical properties of test specimens produced under standard manufacturing conditions, using a Voxeljet VX1000 machine, were assessed for bend and tensile strength, hardness, friability, and surface finish. The physical properties of the 3DP test specimens were then compared with the properties of laboratory hand- rammed test specimens. The results of the investigation suggest that the properties of AM-fabricated sand parts are inferior to sand parts produced by conventional moulding processes.
Highlights
The direct fabrication of foundry moulds and cores is one of the growing applications of additive manufacturing (AM) to sand casting technology [1]
Improved and cost-effective AM processes mainly based on three-dimensional printing (3DP) have replaced older processes such as laser sintering (LS) and fused deposition modelling (FDM) for the direct production of sand moulds and cores ([3, 4])
The investigation revealed that there are important differences in foundry properties between AM and conventional HR sand parts. These differences are essentially due to the difference in structure of sand specimens produced by layer-by-layer manufacturing on one side and by compaction on the other
Summary
The layeredbased manufacturing process has revolutionised traditional sand moulding methods. Crucial characteristics of 3DP sand parts related to strength, dimensional accuracy, and hardness are not wellknown in terms of their magnitude and in comparison with conventionally-moulded sand parts. In this investigation, the physical properties of test specimens produced under standard manufacturing conditions, using a Voxeljet VX1000 machine, were assessed for bend and tensile strength, hardness, friability, and surface finish. ʼn Beter verstaan van die eienskappe van die onderdele, wat met toevoegingsvervaardigingtegnieke produseer word, is egter nodig voordat dit deur die gietbedryf aanvaar gaan word. Die resultate toon dat die toevoegingsvervaardiging monsters se eienskappe slegter as die van konvensioneel gegiete monsters is
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