Finite element modeling and experimental validation of turning process using bio-mimicked structured tool for outcomes relevant to industry

Abstract

Martensitic stainless steels are extensively used in aerospace, medical, and oil and gas industries because of their superior properties such as high hardness, strength, and corrosion resistance properties. However, the machining of this work material becomes difficult due to its high hardness and low thermal conductivity leading to high cutting force requirements and tool wear. Recently, the application of structured tools is one of the sustainable machining techniques used to enhance the machinability of work materials. Most of the researchers have studied only the influence of conventional structured geometries and have mainly concentrated on experiments. But the conduction of experiments involves bulky and costly experimental setups and also consumes a lot of time. Also, the bio-mimicked geometrical shapes and various geometrical parameters of structured tools on machining characteristics of martensitic AISI 420 steel have not been studied. Therefore finite element (FE) modeling proves to be a beneficial technique as it saves time and effort. In the current investigation, a 3D FE model is developed to examine performance of different geometrical structured tools in improving the machinability of AISI 420 steel. Johnson cook (JC) material model is utilized for modeling workpiece. Initially, the tangential force results obtained through simulation are validated with tangential forces obtained through experiments with an error of 6.65% using conventional tool and 5.57% using bio-mimicked structured tool, indicating the suitability of the machining model. Further, the effect of various structure shapes, mainly bio-mimicked crescent structure, dimple structure, and groove structure, was studied, and it is noticed that crescent-structured tool depicted better performances in lowering cutting force, effective stress, and cutting temperature. After getting superior geometry, i.e., crescent-structured geometry, the influence of variation in crescent structure parameters (radius, edge distance) was examined to study its influence on the above-mentioned machining responses. The variation in structure parameters significantly influences various output responses, indicating that bio-mimicked structured tools have a lot of potential to improve the machining performance of AISI 420 steel.