Tool Life and Surface Integrity Characteristics of SLM and C&W Inconel 718 in Dry and MQL Condition

Abstract In this paper, a tool life test was performed using PVD coated insert on Inconel 718 (IN718) samples. The tool life was tested on IN718 workpiece fabricated through conventional (Cast & Wrought) and additive (Selective Laser Melting) process routes. The as-built SLM samples were subjected to two heat treatments such as Hot Isostatic Pressing (HIP) and Aeronautic Heat Treatment (AHT). This study aimed to evaluate the machining behavior of C&W and SLM IN718 from the machining point of view such as tool wear, chip appearance, surface roughness, and residual stresses. The tool life tests were performed under a dry and near dry environment like using Minimum Quantity Lubrication (MQL). Meanwhile, the tool wear propagation under different cutting conditions is also explored. Under both the cutting conditions flank wear and fracture of the cutting edge are the most predominant failure modes minimizing the tool life. The microhardness, surface roughness, and residual stress measurements were analyzed. The result indicates that the microstructural difference between the C&W and SLM has more influence on the tool life compared to the machining environment. On machining, the SLM sample has 80% and 43% more tool life than the C&W in dry and MQL machining. Comparing the dry and MQL machining of SLM, on using MQL the tool life is 30% less compared to the dry machining.