Faculty Publications

Now showing 1 - 4 of 4

Machinability investigations on high chrome white cast iron using multi coated hard carbide tools
(Springer India sanjiv.goswami@springer.co.in, 2014) Ravi, A.M.; Murigendrappa, S.M.; Mukunda, P.G.
This study investigated the performance of multilayer hard coated carbide tool and multi-response optimization of the turning process for an optimal parametric combination to yield the minimum cutting forces and machining power with a maximum material removal rate (MRR) using Taguchi and artificial neural network (ANN) methods. In recent times, high chrome white cast iron finds increasing applications in aerospace, mining, mineral process industries. Its machinability using carbide insert (TiC/TiCN/Al2O3) cutting tool has been studied. The influences of cutting parameters on the cutting forces, MRR and machining power of the process have been analyzed using analysis of variance and the results are correlated using ANN. Linear regression method was used to establish the relation between the cutting parameters and the process responses. The confirmation test reveals that, the accuracy of prediction of ANN is better than that of the regression analysis. In view of the good performance of the carbide tools (at optimum conditions), it can replace the cosly CBN, with improved economic benefits. © 2014 Indian Institute of Metals.
Enhancing the surface integrity characteristics of Al-Li alloy using face milling
(Elsevier B.V., 2022) Marakini, V.; Srinivasa Pai, P.; Udaya Bhat, K.; Thakur, D.S.; Achar, B.P.
This work presents the milling induced surface integrity investigation of Al-Li alloy. The effect of milling on the surface roughness, microhardness, microstructure, and residual stress is studied. Uncoated carbide inserts are used for milling due their superior hardness and greater life, when machining softer materials such as aluminium and its alloys. Results show that the minimum surface roughness (Ra = 0.043 µm) and maximum microhardness (216 HV) are achievable from the milling process, when compared with the roughness (Ra = 0.528 µm) and microhardness (180 HV) of the as-received material. Results indicate limited harm to alloy microstructure from the milling process and the presence of compressive residual stress induced from milling. The work finds scope for aerospace applications. © 2022 Elsevier B.V.
High-speed face milling of AZ91 Mg alloy: Surface integrity investigations
(KeAi Publishing Communications Ltd., 2022) Marakini, V.; Pai, S.P.; Bhat K, U.K.; Thakur, D.S.; Achar, B.P.
Magnesium (Mg) alloys are popular in the aerospace and automotive sector owing to their light-weight aspects. Amongst various Mg alloys, AZ91 alloy behaviour under machining has been trending and needs to be completely explored. The selection of optimal machining parameters is an important decision making process to achieve highest quality along with reduced cost and time. In this regard, this article describes experimental investigations to evaluate the performance of face milling operations on the surface characteristics of AZ91 magnesium alloy. The experiments were carried out with uncoated and PVD (Physical Vapour Deposition) coated carbide inserts at three levels of cutting speed (500, 700 and 900 m/min), feed rate (0.1, 0.2 and 0.3 mm/teeth) and depth of cut (0.5, 1.0 and 1.5 mm) under dry machining conditions. Major surface integrity indicators, such as roughness, hardness, residual stresses and microstructure are analysed. Chip morphology is also analysed and the correlation between chips and machined surface roughness is established. Face milling operation significantly improved surface roughness and microhardness of this alloy. Roughness improvement up to 85% (0.067 μm) and hardness improvement up to 33% (91.8 HV) is observed from the use of uncoated carbide inserts. Whereas, from PVD coated inserts, roughness improvement up to 81% (0.083 μm) and hardness improvement up to 60% (111.2 HV) is achieved. A similarity in behaviour between the two types of insert conditions are observed with increase in roughness from feed increase and decrease in hardness from cutting speed increase. Microstructural analysis showed PVD coated insert conditions producing surface with no defects, when compared to the crack observed in the surface from the use of uncoated carbide inserts. Marginally higher compressive residual stresses are detected at the surfaces from use of the uncoated inserts. Overall, due to no surface defect and the significant improvement in hardness and roughness from the PVD coated inserts, they are recommended for use in face milling operation for the cutting conditions investigated in this study. © 2022 The Authors
Effect of High-Speed Dry Face Milling on Surface Integrity Characteristics of AZ91 Mg Alloy
(Springer, 2023) Marakini, V.; Pai, S.P.; Bhat K, U.K.; Thakur, D.S.; Achar, B.P.
In the present study, high-speed dry face milling is performed on AZ91 magnesium alloy using uncoated carbide inserts. The most influential surface integrity characteristics, such as surface roughness, hardness, microstructure and residual stresses, are investigated for a set of milling parameters chosen from the Taguchi design of experiments. The impact of machining conditions, such as feed rate, cutting speed and depth of cut on the surface integrity characteristics, are identified in order to improve the overall functionality of the alloy. Grey Relational Analysis optimization method is implemented to identify the optimal milling conditions. The results showed that high-speed dry face milling is very influential in improving the overall surface integrity characteristics of this alloy. © 2022, ASM International.

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