An integrated approach to investigate the energy consumption for manufacturing and surface finishing 3D printed Inconel 718 parts

Abstract

Current scenarios show the need of making manufacturing more sustainable as it plays a crucial role in global sustainability. For this reason, sustainability should be included among the objectives driving the selection of process parameters. As-built parts manufactured by additive manufacturing techniques always require post-processing to meet industrial quality requirements, and machining is one of the solutions often adopted to improve their surface finishing. However, inevitably an additional manufacturing process requires some supplementary both energy and resource consumption by also impact unavoidably on the environment. This experimental study includes both additive manufacturing and post-process machining to evaluate the global specific energy consumption required to manufacture and then finish Inconel 718 parts. This paper aims at understanding how to obtain Inconel 718 parts manufactured by selective laser melting (SLM) and machined by turning by saving energy without sacrificing roughness and density. The printing process parameters of SLM process have been varied in a wide range: 27 different samples have been produced to evaluate the specific energy consumption (SEC) and to highlight the influence of the process parameters on the energy consumption. Density and roughness measurements have been chosen as measured outputs to prove the effectiveness of the process and to attempt a correlation among process parameters, properties of the printed parts and energy consumption. All the as-built samples were post-treated by turning process under the same conditions to achieve a surface finishing with a Ra value close to 4 μm; the energy consumption of this process has been also recorded and analyzed. Finally, the energy consumption of the whole processing path, including both printing and turning, has been discussed and a correlation between processing parameters and energy consumption has been attempted. Results showed that a proper choice of the process parameters leads up to a 54% reduction in specific energy consumption to obtain SLMelted Inconel 718 parts having low surface roughness and high density.