35. Analysis of Effect of Heat Treatment on Machining Characteristics During Micro-end Milling of Inconel 718

Miniaturized products are getting great importance in highly growing industries such as aerospace, automobile, and biomedical due to the high demand and great applications of micro part/feature. Out of the different micromachining techniques, micro-end milling is one of the preferred processes because of its flexibility, ability to produce complex part, and high material removal rate. A detailed analysis of cutting force and areal surface roughness during micro-end milling of Inconel 718 is performed to analyze the effect of heat treatment on machining characteristics. The different heat treatments were performed on Inconel 718 at 920 °C. Micro-end milling experiments on different heat-treated samples by varying feed per tooth were conducted. The cutting force was measured using KISTLER dynamometer (9256C2) and areal surface roughness is measured using Alicona 3D optical profiler (Infinite Focus G5). Comparative analyzes of different heat-treated samples were analyzed. It was found that the cutting force, as well as areal surface roughness, shows a similar trend under different heat treatment conditions. At lower feed per tooth higher cutting force was observed with nonlinear pattern due to the higher plowing force. Size effect in cutting force was observed near to 1 µm feed per tooth. Outside the size effect region, both cutting force and areal surface roughness show the trend similar to macro-machining. The minimum value of areal surface roughness is obtained for water quenching condition. The minimum value of areal surface roughness obtained near to 3 µm, which is the cutting edge radius of the micro endmill cutter.