Browsing by Author "Singh Rajput, A.S."

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Design and development of an experimental setup for nanofinishing of exhaust valves using magnetorheological finishing to enhance functional performance
(Springer-Verlag Italia s.r.l., 2025) Sharma, K.; Singh, V.K.; Singh Rajput, A.S.; Das, M.
Exhaust valves in high-performance and racing engines require ultra-smooth surfaces to improve durability and operational efficiency. This study investigates the application of Magnetorheological (MR) polishing for finishing exhaust valve seats. MR fluid, consisting of micron-sized magnetic particles suspended in a carrier liquid, forms a semi-solid structure under a magnetic field, enabling precise surface finishing. An in-house experimental setup was developed, and various magnet configurations were tested to optimize the polishing zone. Computational investigations were conducted to analyze magnetic field distribution for 2-bar, 3-bar, 4-bar, and 5-bar magnet systems, with results validated using a Gauss-meter. Unlike prior MR polishing studies that focused mainly on optical or biomedical components, our work emphasizes automotive engine applications and demonstrates the optimization of a 4-magnet system to achieve uniform magnetic field distribution. The novelty lies in developing a cost-effective, adaptable, and reproducible MR polishing arrangement tailored for curved valve geometries, while addressing reproducibility through detailed experimental parameters. The primary objective was to optimize process parameters for MR polishing. Under optimal conditions—spindle speed of 750 RPM, stand-off distance of 1.5 mm, and polishing time of 17.5 min—the surface roughness (Ra) improved significantly from 0.613 ?m to 0.115 ?m. Measurements were performed using a 3D profilometer. Further surface characterization via Atomic Force Microscopy (AFM) showed a reduction in surface asperities, while Field Emission Scanning Electron Microscopy (FE-SEM) revealed fewer surface scratches. These results confirm the potential of MR polishing as an effective technique for enhancing the surface finish of critical engine components. © The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature 2025.
Hybrid wire arc directed energy deposition and machining approach for realizing density-based functionally graded materials with enhanced strength-to-weight ratios
(Elsevier Ltd, 2025) Sarma, R.; Singh Rajput, A.S.; Kapil, S.; Joshi, S.N.
Wire Arc Directed Energy Deposition (WADED), a high-deposition-rate Additive Manufacturing (AM) technique, enables the rapid fabrication of near-net-shape metallic components. However, achieving Functionally Graded Materials (FGMs) with density variations within the same material remains challenging. This study introduces a novel Hybrid WADED (H-WADED) process to fabricate mono-material FGMs with engineered density gradients tailored for applications in aerospace, nuclear energy, and electromagnetism. In this method, each layer is deposited using WADED, followed by face milling and robotic drilling to introduce controlled holes. The diameter and spacing of the holes are designed to achieve the desired density gradient, enabling up to a 10 % reduction in mass. Experimental results showed 2 mm diameter holes as optimal, minimizing material flow and distortion while improving the strength-to-weight ratio. This innovation also enhances thermal dissipation capabilities, making the components suitable for high-stress environments. Performance evaluation of the fabricated FGMs revealed a 26.2 % reduction in thermal conductivity and significant mitigation of residual stresses due to stress redistribution around the holes. Under compressive loading, the samples exhibited a maximum load capacity of 200 kN. Although tensile strength was reduced by 19.6 % compared to solid samples, elongation remained unaffected, highlighting the structural integrity of the components. This work demonstrates an effective method to fabricate density-based FGMs, providing a practical pathway for developing advanced, lightweight, and thermally efficient components for critical industrial applications. © 2025
Interrupted metal deposition wire arc additive manufacturing to fabricate objects with trailered microstructures
(Elsevier B.V., 2025) Singh, C.P.; Tiwari, V.; Kumar, A.; Kapil, S.; Singh, S.S.; Singh Rajput, A.S.
Advances in additive manufacturing have enabled innovative approaches to creating materials with tailored properties. This study presents Interrupted Metal Deposition in Wire Arc Additive Manufacturing (IMD-WAAM) for fabricating thin walls of Functionally Graded Materials (FGMs). By controlling heat input during deposition, IMD-WAAM precisely modulates microstructural evolution. Characterization techniques, including Optical Emission Spectroscopy (OES) for composition analysis, Field Emission Scanning Electron Microscopy (FESEM), and Electron Backscatter Diffraction (EBSD) for grain-level insights, along with Continuous Cooling Transformation (CCT) diagrams from JMatPro, revealed distinct microstructural zones. Continuous deposition showed coarse ferritic structures, while a 5-second Inter-Drop Cooling Time (IDCT) produced refined ferritic and bainitic structures. These results demonstrate IMD-WAAM's ability to achieve seamless property gradation, making it a transformative method for aerospace, biomedical, and other applications requiring customized material properties. © 2025 Elsevier B.V.
Machine-learning-based optimization of hybrid electrochemical magnetorheological finishing process to achieve nano finishing on additively manufactured biomaterial
(Taylor and Francis Ltd., 2025) Singh Rajput, A.S.; Das, M.; Kapil, S.
Powder Bed Fusion-Laser Beam (PBF-LB) is a form of additive manufacturing that entails the incremental layering of materials to construct complex multi-layered structures. The precise comprehension of the temporal and spatial variations of the entire structure. Individual tracks, layers, and the molten pool are indispensable for regulating aberrant deposition patterns and fabricating targeted PBF-LB components. However, the PBF-LB fabricated parts’ poor surface quality is a significant challenge. The Hybrid Electrochemical Magnetorheological (H-ECMR) polishing technique integrates mechanical abrasion with electrochemical reactions to enhance the surface characteristics of parts created through additive manufacturing. Herein, the Magnetorheological (MR) is used as the polishing media, and its carrier medium is replaced with an electrolyte to enable an electrochemical reaction. In the present work, machine learning-based optimisation, i.e. Artificial Neural Network, is implemented to optimise the process parameters to attain maximum surface reduction. The average surface roughness (Ra) value of 12.56 µm is lowered to 34.56 µm on the Ti-6Al-4 V polished surface at optimised process parameters. Furthermore, the electrochemical reaction between the workpiece and the electrolyte forms a dense and consistent oxide layer on the polished surface, increasing the corrosion resistance of the PBF-LB fabricated part. © 2025 Informa UK Limited, trading as Taylor & Francis Group.
Solar-Driven additive Manufacturing: Design and development of a novel sustainable fabrication process
(Elsevier Ltd, 2025) Hazoary, A.; Panwar, M.; Singh Rajput, A.S.; Kapil, S.
Additive Manufacturing (AM) is revolutionizing industries by enabling layer-by-layer fabrication of complex components. Among AM techniques, Laser Powder Bed Fusion (LPBF) is widely used but is energy-intensive, limiting its sustainability. This study explores the potential of concentrated solar energy as an alternative heat source for sintering Thermoplastic Polyurethane (TPU) in a solar-powered 3D printing process. A custom-designed solar 3D printer, equipped with stepper motors and an Arduino UNO for precise control, was utilized to evaluate critical process parameters such as feed rate, hatch spacing, and layer thickness. The results indicate that feed rate and hatch spacing are pivotal to energy density, directly influencing sintering quality. Optimal sintering occurred at feed rates between 100–200 mm/min, which provided sufficient energy for uniform layer fusion, balancing surface finish and mechanical strength. Larger feed rates resulted in incomplete sintering and weaker parts, while a hatch spacing of 1.67 mm offered efficient pass binding with reduced build time. The study successfully demonstrated the fabrication of multilayer TPU structures using solar energy, achieving mechanical properties comparable to conventional LPBF techniques. This solar-powered approach underscores the potential for integrating renewable energy into additive manufacturing, offering a sustainable alternative to laser-based systems. Future refinements, such as dynamic solar tracking and real-time parameter adjustments, could further enhance its industrial viability. By leveraging renewable energy, this research represents a significant step toward eco-friendly manufacturing solutions, reducing energy consumption and carbon footprint while maintaining high-quality outputs. © 2025 International Solar Energy Society