Validation of a low-cost selective powder deposition process through the characterization of tin bronze specimens

Abstract

Additive manufacturing technologies are becoming increasingly popular due to their advantages over traditional subtracting manufacturing technologies. Despite advances in this field, fixed and maintenance costs for additive manufacturing with metals remain high. The introduction of low-cost metal machines in the additive manufacturing market considerably reduces the cost of acquiring and maintaining this type of equipment. This work aims to establish the process requirements for a low-cost selective powder deposition process, and validate it through the production of specimens in the laboratory and evaluate their mechanical properties. Tin bronze specimens were produced under different manufacturing conditions, namely powder dimensions, type of crucible and coke, firing segments and casting strategy. The morphology and chemical composition of the specimens were carried out combining the scanning electron microscopy and energy dispersive X-Ray spectroscopy techniques, respectively. It was observed that crucibles and coke with impurities that react with the metal powders and infill in a reducing atmosphere have influence in the final quality of parts. Tested samples displayed high variability of results which can be correlated with different manufacturing conditions. The selection of the appropriate print parameters led to the manufacture of tin bronze specimens with mechanical properties comparable to those reported in the literature. Overall, low-cost selective powder deposition is a promising technology, if identified manufacturing issues are addressed.