Study on Drilling of Additively Manufactured Inconel 718

Inconel 718 Ni-based super alloy was fabricated through selective laser melting (SLM) technique. Drilling operation was performed on the cylindrical component produced through SLM technique. During drilling process the thrust force was measured by varying the process parameters like drilling speed and feed rate. Near net shape component can be produced through SLM process and in case a need for additional machining operation like drilling is required for assembly purpose, this report will help to understand the behavior of the material and selection of optimum cutting parameters. A case study is presented, with a view to understand the drilling operation on a Metal Additive Manufactured part analyzing the thrust force with respect to varying two process parameters, i.e. feed rate and revolution of drilling bit, is studied and presented with the experimental results. A component with a hole of a particular diameter manufactured in an SLM process, the exact dimension of the hole is difficult to obtain because of the down skin/up skin melting zone which is inherent in this manufacturing process. Hence drilling operation needs to be carried out to get the hole with exact dimension and surface finish. This paper presents the optimum revolution and feed rate for desired dimensional accuracy and finish.