Browsing by Author "Korgal, A."

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A Review of Optimization and Measurement Techniques of the Friction Stir Welding (FSW) Process
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Prabhakar, D.A.P.; Korgal, A.; Shettigar, A.K.; Herbert, M.A.; Gowdru Chandrashekarappa, M.P.G.; Pimenov, D.Y.; Giasin, K.
This review reports on the influencing parameters on the joining parts quality of tools and techniques applied for conducting process analysis and optimizing the friction stir welding process (FSW). The important FSW parameters affecting the joint quality are the rotational speed, tilt angle, traverse speed, axial force, and tool profile geometry. Data were collected corresponding to different processing materials and their process outcomes were analyzed using different experimental techniques. The optimization techniques were analyzed, highlighting their potential advantages and limitations. Process measurement techniques enable feedback collection during the process using sensors (force, torque, power, and temperature data) integrated with FSW machines. The use of signal processing coupled with artificial intelligence and machine learning algorithms produced better weld quality was discussed. © 2023 by the authors.
Advances in micro electro discharge machining of biomaterials: a review on processes, industrial applications, and current challenges
(Taylor and Francis Ltd., 2024) Korgal, A.; Shettigar, A.K.; Karanth P, N.; Prabhakar, D.A.P.
Micro Electro-Discharge Machining is a precision machining process that uses electrical discharge to produce small-scale components with high accuracy. A metal workpiece is machined in this process by repeatedly generating spark between a tool electrode and the workpiece, removing material in a controlled manner. The significance of µ-EDM lies in its ability to produce highly accurate and complex components with a high surface finish, making it ideal for use in various industries, including aerospace, medical, and electronics. The critical parameters to the success of µ-EDM include the electrical discharge energy, voltage, current, pulse duration, and spark gap between the tool electrode and workpiece, including the shape and size of the tool electrode. This review article discusses the µ-EDM process used to machine biological materials and also examines the µ-EDM, dry µ-EDM procedure, and the features of biomedical materials for biocompatibility, 3D micro shape machining with tool wear composition, and thin film coating for microelectrodes. The impact of introducing nanoparticles to dielectric fluids is further clarified in this article. This study addresses the prospective future research subjects and application areas for the µ-EDM process in order to fulfill the demanding criteria for biomaterials and their usage in the production of bioimplants. © 2024 Taylor & Francis Group, LLC.
Electro-discharge machining of microholes on 3d printed Hastelloy using the novel tool-feeding approach
(KeAi Publishing Communications Ltd., 2025) Korgal, A.; Shettigar, A.K.; P, N.K.; Kumar, N.; Bindu Madhavi, B.M.
Hastelloy, a nickel-based superalloy renowned for its exceptional resistance to corrosion at high temperatures, is widely used in sectors such as nuclear, aerospace, chemical processing, and pharmaceuticals. Microelectrical discharge machining (?-EDM) is crucial for generating microholes and channels on Hastelloy. Since it effectively addresses difficulties like work hardening, high strength & wear resistance, and low thermal conductivity in traditional machining. Microholes play a major role in many critical components for precise control of fluids in fuel injectors, managing heat in turbine blades, controlled gas exchange, etc. The current research investigates the drilling of 8:1 aspect ratio microholes machined by 400 ?m diameter electrodes. This study investigated the influence of tool material (tungsten carbide, carbide drill bit, and brass) on ?-EDM performance. Compared to tungsten carbide and carbide drill bits, brass exhibited significantly lower electrode wear, leading to more precise microholes with reduced overcut and taper angle. However, brass also required a substantially longer machining time. Carbide drill bits offered a balance between wear resistance, machining time, and overcut/taper angle. © 2024 The Authors
Exploring welding parameter effects on friction stir weld joints in aluminum 8006 alloy using response surface methodology
(MIM RESEARCH GROUP, 2025) Chandrakumar, C.; Sogalad, I.; Shettigar, A.K.; Korgal, A.; Nagaral, M.
This study aims to develop mathematical models that can predict the characteristics related to mechanics, such as microhardness and impact resistance, of Aluminum that has been friction stir-welded 8006 alloy joints with 95% confidence. The four process parameters tool tilt angle, welding speed, tool pin shape, and rotating speed were systematically varied across three levels. Following a response surface and central composite design approach that is face-centered, the influence of different factors on the mechanical properties of aluminum 8006 alloy joints was assessed. The highest impact toughness of 58 joules was observed in joints specially prepared by a cylindrical threaded pin profile tool with a 1° tilt angle operating at 800 RPM and a feed rate of 20 mm/min and test was conducted at room temperature. Additionally, it was investigated how process factors affected impact toughness by ANOVA and the results revealed that the tool pin geometry is identified as the most significant process variable on impact toughness, contributing 52.52%, thereafter the tool tilt angles (15.53%), rotating speed (8.80%), and welding speeds (5.84%). The findings showed that, for impact toughness, the tool tilt angle and pin shape were more important than welding speed and tool rotation speed, but the tool pin profile and the welding speed showed governance over rotational speed and angle of tilt in case of hardness. The joints achieved a maximum hardness of 166 VHN at stir zone of the welded specimen made from a threadless taper pin tool for the speed of 1200 rpm, the tool was tilted at 2 degrees while welding at a speed of 40 mm/min. Finally, the effects of process parameters on the microstructure of friction stir welded Aluminum 8006 alloys were addressed and discussed. © 2025 MIM Research Group. All rights reserved.
Investigation of the effect of process parameters on the mechanical properties of friction stir additive manufactured (FSAM) AA8090 alloy
(Elsevier B.V., 2025) D A P, P.; Shettigar, A.K.; Herbert, M.A.; Korgal, A.; Adiga, K.
Friction Stir Additive Manufacturing (FSAM), an emerging technique, falls under the category of sheet lamination additive manufacturing. It employs a layer-by-layer fabrication where all the plates should be flat and of the same size. This process was developed to fabricate near-net-shaped components and refined microstructures. FSAM has been extensively used in the fabrication of aluminum alloys for aerospace applications. In this work, FSAM has been carried out for AA8090 aluminum alloy. AA8090 is the second-generation Al-Li alloy with 2.3 % Li, lightweight, 10 % lower density and 11 % higher modulus than the existing commercial 2014 and 2024 Al alloy. The experiments were carried out at rotational speed (1000 – 2000 rpm), traverse speed (45–55 mm/min) and 1° constant tilt angle. The macrostructure and microstructure analysis were carried out. This was followed by microhardness and tensile test analysis. The microhardness was carried out at nine points on each layer and tensile specimen was made according to ASTM E8 standard. The maximum reduction in grain size, which is 62 %, maximum hardness value 113 HV and maximum tensile value 346.8 MPa were observed at 2000 rpm. The size of the grains decreased from the top layer into the bottom layers. The maximum hardness for all the experiments was observed in the re-stir zone of the specimens. It was concluded that with increase in process parameters, better mechanical and microstructural properties can be achieved. The fractography analysis showed the presence of dimples and tear ridges indicating a ductile fracture. © © 2025. Published by Elsevier B.V.
Optimization of micro-WEDG parameters ?for high-precision machining of Nimonic-C263
(SAGE Publications Ltd, 2025) Das, M.; Jagtap, M.; Karande, P.; Tayade, R.M.; Korgal, A.
Nimonic-C263, known for its high density, durability, and corrosion resistance, poses significant challenges to conventional machining in terms of maintaining dimensional accuracy and surface quality. To address these issues, this study investigates the use of micro-wire electro-discharge grinding (m-WEDG), an advanced machining technique suited for fabricating precision micro-tools from hard-to-machine materials. The process parameters—spindle speed (SS), voltage (V), and capacitance (C)—were optimized to minimize surface roughness (Ra) and maximize material removal rate (MRR). A 400 µm micro-pin was fabricated from a 1 mm diameter Nimonic-C263 rod to evaluate machining performance. Using the Taguchi method, optimal conditions achieved an MRR of 0.20 mm³/min and a Raof 1.670 µm. Computational modeling was employed to analyze the parametric effects, confirming improvements in machining efficiency. Surface analysis via energy dispersive spectroscopy (EDS) revealed pyrolytic oxygen and carbon deposition, while field emission scanning electron microscopy (FESEM) showed minor surface waviness. This study provides a theoretical framework linking process parameters to machining performance, contributing to advancements in precision micro-manufacturing. © The Author(s) 2025