Browsing by Author "Prabhakar, D.A.P."

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A comprehensive review of friction stir techniques in structural materials and alloys: challenges and trends
(Elsevier Editora Ltda, 2022) Prabhakar, D.A.P.; Shettigar, A.; Herbert, M.A.; Gowdru Chandrashekarappa, M.; Pimenov, D.Y.; Giasin, K.; Prakash, C.
Friction-stir techniques are the potential alternative to fusion-based systems for processing and welding metallic alloys and other materials. This review explores the advantages, applications, limitations, and future directions of seven friction-based techniques namely, Additive Friction Stir Deposition (AFSD), Friction Stir Additive Manufacturing (FSAM), Friction Stir Welding (FSW), Friction Stir Processing (FSP), Friction Surfacing (FS), Friction Stir Spot Welding (FSSW), and Friction Stir Lap Welding (FSLW). The basic underlying principle of these processes uses friction as a thermal energy source to weld/process/deposit materials. The common control parameters of all friction stir processing techniques are axial force, rotational speed, and weld or traverse speed. In addition, tool profiles and tool dimensions are known to influence the weld quality. The tool's rotational speed and axial force generate friction between the workpiece and tool material interface, which could plasticize the material. The additive powder bed friction stir process (APBFSP) is another new solid-state manufacturing technique that focus on fabricating the polymer matrix nanocomposites (PNC). In this, a hollow tool like AFSD and the fundamental principle of FSP are combined. The said parameters affect the quantity of material getting deposited/welded. However, weld speed/traverse speed alters the weld quality, and higher traverse speed results in porosity and voids in the welded/deposited/processed region. The only difference between AFSD and other friction stir techniques (FSTs) is that in the AFSD technique, the hollow rotating tool comprises two protrusions with different tool profiles (cylindrical, threaded cylindrical, and tapered cylindrical, square) used. Threaded cylindrical profile and tool steel as the tool material is the most commonly employed in FSTs. Apart from that, tungsten carbide is preferred for hard materials. The working principles and process parameters of FSTs that affect the part quality are discussed in detail. The above review gives the reader an understanding of the domain of FSTs that can be researched further. A summary of some of the potential research works with objectives, process parameters, and outcomes is highlighted. This will provide the readers with an overview of the work carried out by researchers across the globe. Finally, the potential research gaps for future directions to be explored soon across the globe are outlined. © 2022 The Author(s).
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.