Industrial and Manufacturing Engineering, Mechanical Engineering, Engineering
72
Scopus Publications
1445
Scholar Citations
21
Scholar h-index
43
Scholar i10-index
Scopus Publications
Investigating the transition from ploughing to shearing in micromilling of additively manufactured Ti6Al4V Sharib Imam, Gaurav Saraf, Chandrakant K. Nirala, Anupam Agrawal Nanotechnology and Precision Engineering, 2026 Compared with wrought Ti6Al4V, additively manufactured (AM) Ti6Al4V exhibits more severe machining difficulties owing to its lower thermal conductivity and higher hardness. AM components often possess lower ductility, anisotropic microstructures, residual stresses, and porosity-related defects, further complicating post-printing micromachining. With the growing demand for miniaturized and high-precision components, micromilling remains a crucial technique for producing features such as microgrooves and channels, and is expected to retain its importance for machining AM Ti6Al4V. However, micromilling faces challenges such as ploughing, excessive tool wear, and high specific cutting forces. This study examines the influence of ploughing and shearing on tool wear, surface morphology, burr width, surface roughness, and specific cutting force across varying feed rates and axial depths of cut. The results indicate a transition from ploughing to shearing as the feed rate and depth increase, improving cutting efficiency. Surface morphology efficiency improves from 81% to 97% (width) and from 75% to 98% (depth). Tool wear is highest at low feed rates and shallow depths owing to rubbing, while larger depths increase wear owing to greater tool engagement. Intermediate depths showed reduced wear. The percentage difference between experimental and ideal specific cutting forces decreases from 63% to 4% with increasing feed rate and depth. Surface roughness improves with increasing feed, but deteriorates at the highest depths, while burr width decreases with both parameters.
Experimental and numerical investigation on heat dissipation capability of micro-pillar textured cutting tools Gaurav Saraf, Gaurav Sharma, Rahul Kumar, Chandrakant K. Nirala Scientific Reports, 2025 In metal cutting, the extreme tool temperature restricts the material removal rate. To address this, it is crucial to adopt techniques that reduce heat input and enhance heat dissipation from the cutting tool inserts. Rake surface texturing, particularly with micro-pillars, is gaining popularity in this context. Direct measurement of the cutting tool temperature is exceptionally challenging, so a numerical approach is adopted in this work to inverse estimate the tool tip temperature based on the temperature measured at a distant location from the rake face. Stage I of the work involved the development of a circular micro-pillar array on tungsten carbide inserts using the Reverse Micro Electrical Discharge Machining (RµEDM) technique. Based on the discharge pulses recorded during RµEDM, the 110V-100 nF voltage-capacitance combination proved feasible for this operation. In Stage II, turning operations were performed on Ti6Al4V alloys under dry, compressed air, and wet conditions. The tool temperature measured at the distant location revealed a substantial temperature drop for textured tools. This is attributed to the reduced contact area at the interface, as observed from the rake morphology of the tools, and to the enhanced heat dissipation from the higher surface area of the developed textures, as revealed by the computational fluid dynamics-based numerical study in Stage III of the work. An array of closely spaced, small-diameter, and higher-depth micro-pillars beyond the tool-chip contact area could enhance heat dissipation from the cutting tools.
Computational evaluation based case study of Schwarz-P TPMS lattice architectures for heat sink thermal performance Syed Hammad Mian, Chandrakant K. Nirala, Ravi Kant, Usama Umer Case Studies in Thermal Engineering, 2025 High-powered electronics are particularly vulnerable to the issue of increased failure brought on by excessive heat buildup. Intricately structured heat sinks, such as triply periodic minimal surfaces, have demonstrated capabilities, but their heat transfer performance are not yet fully understood. The goal of this study is to investigate the flow and heat transfer characteristics of the Schwarz-P heat sink via computational fluid dynamics. It evaluates the impact of unit cell size and porosity on the thermal performance of the Schwarz-P heat sink. The effectiveness of Schwarz-P-structure in relation to a plate-fin heat sink is also analyzed. The results indicate less tortuosity and that most of the fluid primarily flows through the central channel of the Schwarz-P heatsink. Flow separation is seen to be taking place when the fluid moves forward and confronts a change in the geometry. Flow reattachment and the development of recirculation zones are seen over a range of cross-sections. It is also noted that the thermal performance of the heat sink with the Schwarz-P structure has been enhanced compared to that of the plate-fin heat sink. This study is valuable as it outlines the relationships between the Schwarz-P heat sinks' design parameters and their thermal performance.
Numerical Evaluation of Roughness Effect on the Thermal Performance of the Schwarz-P-Based TPMS Heat Sink Syed Hammad Mian, Chandrakant K. Nirala, Ravi Kant, Usama Umer, Hreetabh Kishore IEEE Access, 2025 Triply Periodic Minimal Surfaces (TPMSs) offer compact geometry and enhanced thermal performance, making them attractive for heat sink applications. However, their complex structures pose manufacturing challenges, typically addressed through additive manufacturing (AM), which inherently produces rough-textured surfaces. While surface roughness significantly influences heat transfer, most numerical studies assume smooth surfaces. While some earlier studies have established the impact of surface roughness on heat transfer, they often overlook the overestimation of heat transfer enhancements. This oversight leads to inaccuracies in predicting the actual thermal performance of these structures. By addressing this gap, this work provides an accurate assessment of the influence of surface roughness on TPMS heat sinks thermal performance. A computational fluid dynamics (CFD) model using the SST k-ω turbulence model with surface roughness and thermal correction is developed. The findings demonstrate that surface roughness enhances thermal performance; for instance, a Schwarz-P heat sink with roughness of 20 μm shows an improvement of approximately 18%. In addition, neglecting the thermal correction in the surface roughness model leads to an overestimation of the heat transfer coefficient by about 13% for the same roughness level. The superior thermal performance of rough-surface heat sinks is attributed to higher effective heat transfer area and increased turbulent kinetic energy, which collectively enhance the heat transfer coefficient, but at the expense of a higher pressure drop. The study provides valuable insights but also highlights the scope for further research. Future investigations should prioritize validating numerical results through experimental testing, exploring alternative roughness models, and incorporating additional empirical relationships to translate measured surface roughness values effectively.
Investigating the transition from ploughing to shearing in micromilling of additively manufactured Ti6Al4V S Imam, G Saraf, CK Nirala, A Agrawal Nanotechnology and Precision Engineering 9 (1), 033004 , 2026 2026
A Size-Effect-Driven Strategy to Improve Tribological Performance in Sustainable Micro-Incremental Forming of Titanium Foils with Solid Lubricants M Pal, A Agrawal, CK Nirala Tribology Transactions 69 (1), 183-196 , 2026 2026 Citations: 1
Numerical Evaluation of Roughness Effect on the Thermal Performance of the Schwarz-P-based TPMS Heat Sink SH Mian, CK Nirala, R Kant, U Umer, H Kishore IEEE Access, doi: 10.1109/ACCESS.2025.3627964 , 2025 2025 Citations: 1
Influence of Grain Size on Formability in Micro-Incremental Sheet Forming M Pal, A Agrawal, CK Nirala Micro Manufacturing: Proceedings of the AIMTDR 2023, 73 , 2025 2025
Computational evaluation based case study of Schwarz-P TPMS lattice architectures for heat sink thermal performance SH Mian, CK Nirala, R Kant, U Umer Case Studies in Thermal Engineering 72, 106273 , 2025 2025 Citations: 7
Mechanical, Viscoelastic and Soil Degradation Performance of Hemp Fiber Reinforced Bio-PBS Composites Developed via Microwave Processing A Sharma, S Zafar, CK Nirala Fibers and Polymers 26 (5), 2175-2188 , 2025 2025 Citations: 9
Experimental and numerical investigation on heat dissipation capability of micro-pillar textured cutting tools G Saraf, G Sharma, R Kumar, CK Nirala Scientific Reports 15 (1), 12282 , 2025 2025 Citations: 6
Tribological performance in micro-milling of Ti6Al4V under nanofluid-based minimum quantity lubrication J Airao, A Jain, CK Nirala, D Unune International Journal on Interactive Design and Manufacturing (IJIDeM) 19 (3 … , 2025 2025 Citations: 8
Bayesian neural networks modeling for tool wear prediction in milling Al 6061 T6 under MQL conditions J Airao, A Gupta, CK Nirala, A Hsue The International Journal of Advanced Manufacturing Technology, https://doi … , 2024 2024 Citations: 8
Sustainable approach for machining of Ti6Al4V using micro-pillar textured turning tool insert G Saraf, H Sutrave, Ninad, K Nirala, Chandrakant Sustainable Materials and Technologies 40 (e00929) , 2024 2024 Citations: 22
Enhancing formability in Micro-Incremental sheet forming by a novel stacking method of ultra-thin sheets M Pal, A Agrawal, N C K Manufacturing letters , 2024 2024 Citations: 7
Determining Critical Wall Angle in Micro-incremental Sheet Forming of SS316L Foils for Formability M Pal, V Pandya, CK Nirala, A Agrawal Numerical Methods in Industrial Forming Processes: Numiform 2023, 273 , 2024 2024
Comparative analysis of single-crater parameters in ultrasonic-assisted and unassisted micro-EDM of Ti6Al4V using discharge plasma imaging S Raza, CK Nirala Nanotechnol. Precis. Eng. 7 (2), 023002 , 2024 2024 Citations: 1
Machinability analysis of additively manufactured Ti6Al4V using micro-pillar textured tool under various cutting fluid strategies G Saraf, S Imam, CK Nirala WEAR 557 (2024), 205514 , 2024 2024 Citations: 23
Multiphysics modelling and high-speed imaging-based validation of discharge plasma in micro-EDM KP Rajurkar, S Raza, CK Nirala, H Kishore 2024
Robotic tool-path generation for complex and overhang-angled parts through offline programming E Singla, S Rathor, R Kant, S Kumar, CK Nirala 2024
Thermal performance index based characterization and experimental validation for heat dissipation by unconventional arrayed micro pin-fins A Agrawal, CK Nirala, H Kishore 2024
An overview of techniques for monitoring and compensating tool wear in micro-electrical discharge machining R Nadda, CK Nirala, PK Singh, D Lee, R Kumar, T Singh Heliyon 10 (e26784) , 2024 2024 Citations: 12
Experimental investigation of micro-pillar textured WC inserts during turning of Ti6Al4V under various cutting fluid strategies G Saraf, CK Nirala Journal of Manufacturing Processes 113, 61-75 , 2024 2024 Citations: 36
An investigation of the formability of ultra-thin CP-Ti-Gr2 foils considering thickness-to-grain-size effects under controlled heat treatment in μ-ISF M Pal, A Agrawal, CK Nirala Journal of Manufacturing Processes 131 (2024), 1202-1218 , 2024 2024 Citations: 9
MOST CITED SCHOLAR PUBLICATIONS
Sustainable cooling strategies to reduce tool wear, power consumption and surface roughness during ultrasonic assisted turning of Ti-6Al-4V J Airao, CK Nirala, R Bertolini, GM Krolczyk, N Khanna Tribology International, 107494 , 2022 2022 Citations: 154
Novel sustainable cryo-lubrication strategies for reducing tool wear during ultrasonic-assisted turning of Inconel 718 N Khanna, J Airao, CK Nirala, GM Krolczyk Tribology International 174, 107728 , 2022 2022 Citations: 72
Accuracy and quality of micro-holes in vibration assisted micro-electro-discharge drilling of Inconel 718 DR Unune, CK Nirala, HS Mali Measurement 135, 424-437 , 2019 2019 Citations: 60
Novel use of ultrasonic-assisted turning in conjunction with cryogenic and lubrication techniques to analyze the machinability of Inconel 718 J Airao, CK Nirala, N Khanna Journal of Manufacturing Processes 81, 962–975 , 2022 2022 Citations: 57
Precise μEDM-drilling using real-time indirect tool wear compensation CK Nirala, P Saha Journal of Materials Processing Technology 240 (1), 176–189 , 2017 2017 Citations: 57
ANN-NSGA-II dual approach for modeling and optimization in abrasive mixed electro discharge diamond grinding of Monel K-500 U DR, N CK, M HS Engineering Science and Technology, an International Journal 21 (3), 322-329 , 2018 2018 Citations: 55
Comparative analysis of tool wear in micro-milling of wrought and selective laser melted Ti6Al4V J Airao, H Kishore, CK Nirala Wear , 2023 2023 Citations: 50
Measurement and analysis of tool wear and surface characteristics in micro turning of SLM Ti6Al4V and wrought Ti6Al4V J Airao, H Kishore, CK Nirala Measurement , 2022 2022 Citations: 49
Tool wear reduction in machining Inconel 718 by using novel sustainable cryo-lubrication techniques J Airao, N Khanna, CK Nirala Tribology International, 107813 , 2022 2022 Citations: 47
Sustainability analysis of new hybrid cooling/lubrication strategies during machining Ti6Al4V and Inconel 718 alloys N Khanna, J Airao, G Kshitij, CK Nirala, H Hegab Sustainable Materials and Technologies , 2023 2023 Citations: 46
Evaluation of μEDM-drilling and μEDM-dressing performances based on online monitoring of discharge gap conditions CK Nirala, P Saha The International Journal of Advanced Manufacturing Technology, 1-18 , 2015 2015 Citations: 42
Experimental investigation of micro-pillar textured WC inserts during turning of Ti6Al4V under various cutting fluid strategies G Saraf, CK Nirala Journal of Manufacturing Processes 113, 61-75 , 2024 2024 Citations: 36
Tool Wear Analysis during Ultrasonic Assisted Turning of Nimonic-90 under Dry and Wet Conditions J Airao, CK Nirala, LNL de Lacalle, N Khanna Metals 11 (8), 1253 , 2021 2021 Citations: 30
A new approach of tool wear monitoring and compensation in RµEDM process CK Nirala, P Saha Materials and Manufacturing Processes 31 (4), 483-494 , 2016 2016 Citations: 30
Micro-electrical discharge machining processes G Kibria, MP Jahan, B Bhattacharyya Technologies and Applications; Springer: Singapore , 2019 2019 Citations: 29
Machinability of Ti-6Al-4V and Nimonic-90 in ultrasonic-assisted turning under sustainable cutting fluid J Airao, CK Nirala Materials Today: Proceedings , 2022 2022 Citations: 28
Multiphysics modelling and high-speed imaging-based validation of discharge plasma in micro-EDM S Raza, H Kishore, CK Nirala, KP Rajurkar CIRP Journal of Manufacturing Science and Technology 43, 15-29 , 2023 2023 Citations: 27
Machinability analysis of Titanium 64 using ultrasonic vibration and vegetable oil J Airao, CK Nirala Materials and Manufacturing Processes , 2022 2022 Citations: 26
Thermal modeling of single discharge in prospect of tool wear compensation in μEDM R Nadda, CK Nirala The International Journal of Advanced Manufacturing Technology 107 (11 … , 2020 2020 Citations: 24
Machinability analysis of additively manufactured Ti6Al4V using micro-pillar textured tool under various cutting fluid strategies G Saraf, S Imam, CK Nirala WEAR 557 (2024), 205514 , 2024 2024 Citations: 23
