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Vinod A.R.,Central Manufacturing Technology Institute | Srinivasa C.K.,Central Manufacturing Technology Institute | Keshavamurthy R.,Central Manufacturing Technology Institute | Shashikumar P.V.,Central Manufacturing Technology Institute
Rapid Prototyping Journal | Year: 2016

Purpose - This paper aims to focus on reducing lead-time and energy consumption for laser-based metal deposition of Inconel-625 superalloy and to investigate the effect of process parameters on microstructure, density, surface roughness, dimensional accuracy and microhardness. Design/methodology/approach - Inconel material was deposited on steel substrate by varying process parameters such as laser power, laser scan speed and powder flow rate. The deposited parts were characterized for their density, surface roughness, dimensional accuracy and microhardness. Findings - The study reveals that with increase in laser power, laser scan speed and powder flow rate, there was an increase in density, surface roughness values and microhardness of the deposits, while there was a decrease in dimensional accuracy, deposition time and energy consumption. Practical implications - The results of this study can be useful in fabrication of Inconel components by laser-based metal deposition process, and the methodology can be expanded to other materials to reduce the lead-time and energy consumption effectively. Originality/value - The present study gives an understanding of effect of process parameters on density, surface roughness, dimensional accuracy, microhardness, deposition time and energy consumption for laser-based metal deposition of Inconel-625. © 2016 Emerald Group Publishing Limited.

Natarajan U.,Alagappa Chettiar College of Engineering And Technology | Chellamalai M.,Central Manufacturing Technology Institute
International Journal of Materials Engineering Innovation | Year: 2011

Response surface methodology (RSM) helps the engineers to raise a mathematical model to represent the behaviour of system as a convincing function of process parameters. This paper investigated the influence of three micro-turning process parameters, which were cutting speed (A), feed rate (B) and depth of cut (C). The response variables were average surface roughness (Ra), tool wear ratio (TWR) and metal removal rate (MRR). Statistical models of these output responses were developed using three-level full factorial design of experiment. The developed models were used for multi-response optimisation by desirability function approach to obtain minimum Ra TWR and maximum MRR. Maximum desirability was found to be 86.63%. The optimised values of Ra, TWR and MRR were 0.0295 μm, 0.0272, 0.098 mg/min respectively for 1101.94 rpm cutting speed, 10 μm/sec feed rate, 0.20 μm depth of cut. Optimised machining parameters were used in verification experiments, where the responses were found very close to the predicted values. © 2011 Inderscience Enterprises Ltd.

Natarajan U.,Alagappa Chettiar College of Engineering And Technology | Chellamalai M.,Central Manufacturing Technology Institute
Machine Vision and Applications | Year: 2013

In this paper, a new attempt has been made in the area of tool-based micromachining for automated, non-contact, and flexible prediction of quality responses such as average surface roughness (R a), tool wear ratio (TWR) and metal removal rate (MRR) of micro-turned miniaturized parts through a machine vision system (MVS) which is integrated with an adaptive neuro-fuzzy inference system (ANFIS). The images of machined surface grabbed by the MVS could be extracted using the algorithm developed in this work, to get the features of image texture [average gray level (G a)]. This work presents an area-based surface characterization technique which applies the basic light scattering principles used in other optimal optical measurement systems. These principles are applied in a novel fashion which is especially suitable for in-process prediction and control. The main objective of this study is to design an ANFIS for estimation of R a, TWR, and MRR in micro-turning process. Cutting speed (S), feed rate (F), depth of cut (D), G a were taken as input parameters and R a, TWR, MRR as the output parameters. The results obtained from the ANFIS model were compared with experimental values. It is found that the predicted values of the responses are in good agreement with the experimental values. © 2011 Springer-Verlag.

Joel Johnson R.D.,Karunya University | Ugrasen G.,Central Manufacturing Technology Institute
Applied Mechanics and Materials | Year: 2014

In this present work, Investigation was carried on the surface of laser dressed super abrasive grinding wheel o study the topography of the super abrasive wheel surface, the residual stress distribution on the laser dressed surface of the wheel and to analyse the heat affected zone of the wheel surface. To investigate all this terms the experimental study of Scanning Electron Microscope and Raman Spectroscopy on the laser dressed wheel surface were done and objective of this work is also to show the effectiveness of laser dressing by measuring the surface roughness of the workpiece before and after laser dressing operation. © (2014) Trans Tech Publications, Switzerland.

Goswami A.,Indian Institute of Science | Ankit K.,Central Manufacturing Technology Institute | Balashanmugam N.,Central Manufacturing Technology Institute | Umarji A.M.,Indian Institute of Science | Madras G.,Indian Institute of Science
Ceramics International | Year: 2014

Microstereolithography (MSL) is a rapid prototyping technique to fabricate complex three-dimensional (3D) structure in the microdomain involving different materials such as polymers and ceramics. The present effort is to fabricate microdimensional ceramics by the MSL system from a non-aqueous colloidal slurry of alumina. This slurry predominantly consists of two phases i.e. sub-micrometer solid alumina particles and non-aqueous reactive difunctional and trifunctional acrylates with inert diluent. The first part of the work involves the study of the stability and viscosity of the slurry using different concentrations of trioctyl phosphine oxide (TOPO) as a dispersant. Based on the optimization, the highest achievable solid loadings of alumina has been determined for this particular colloidal suspension. The second part of the study highlights the fabrication of several micro-dimensional alumina structures by the MSL system. © 2013 Elsevier Ltd and Techna Group S.r.l.

Srinivasa C.K.,Central Manufacturing Technology Institute | Ramesh C.S.,PES Institute of Technology | Prabhakar S.K.,Central Manufacturing Technology Institute
Rapid Prototyping Journal | Year: 2010

Purpose - The purpose of this paper is to study the effect of blending time, SiC content and fill ratio on the homogeneity of iron-silicon carbide powder mixture, blended in double-cone blender; to evaluate density, microstructure and micro hardness of laser sintered iron and iron-SiC specimens; and study the feasibility of building a complex iron-SiC metal matrix composite (MMC) part by direct metal laser sintering (DMLS) process. Design/methodology/ approach - The morphology and particle size of iron and silicon carbide powders were evaluated. Nickel coating was carried out on silicon carbide particles. Blending of iron-SiC powders were carried out in two phases in a double-cone blending equipment. In the first phase, three tests were conducted with fill ratios (ratio of volume of conical blender to volume of powder mixture) of 1.68, 3.39, and 6.8 percent while iron-SiC weight ratio was kept constant at 97:3. In the second phase, four tests were conducted with iron-SiC weight ratios of 99:1, 98:2, 97:3, and 95:5 while keeping a constant fill ratio of 1.68 percent. In both the phases, blending was carried out for duration of 43 minutes. Homogeneity of the powder mixture was evaluated at different intervals of time by adopting sampling process. Sintering was carried out on iron and iron-SiC powder mixture using DMLS machine at laser speed of 50, 75, 100, and 125 mm/s. Microstructure, density and micro hardness studies were carried out on the sintered specimens. A 3D model of a part with complex geometry was modeled using Unigraphics CAD/CAM software and prototype part was built by DMLS technology using the blended iron-2 weight percent SiC powder. Findings - A reduction in blending time was observed with increase in SiC content and decrease in fill ratio. Microstructure and micro hardness tests conducted on laser sintered iron-silicon carbide specimens, reveal the homogeneity of blended powder. The density of the iron-SiC composites sintered at a laser speed of 50 and 75 mm/s, decreased with increase in SiC content. Further, an increase in the micro hardness of iron-SiC composites was observed with increase in SiC content and decrease in laser speed. Complex functional part was built by DMLS technology with out any supports. Research limitations/implications - The experiments were conducted with standard blending equipment in which the speed is limited to 48 revolutions per minute only. Originality/value - Meager information is available on blending of powders for producing MMCs by laser sintering process. The work presented in this paper will be a guideline for researchers to carry out further work in blending of powders for producing MMCs by rapid prototyping process. © Emerald Group Publishing Limited [ISSN 1355-2546].

Bhaskaran J.,B.S. Abdur Rahman University | Murugan M.,B.S. Abdur Rahman University | Balashanmugam N.,Central Manufacturing Technology Institute | Chellamalai M.,Central Manufacturing Technology Institute
Journal of Mechanical Science and Technology | Year: 2012

Monitoring of tool wear during hard turning is essential. Many investigators have analyzed the acoustic emission (AE) signals generated during machining to understand the metal cutting process and for monitoring tool wear and failure. In the current study on hard turning, the skew and kurtosis parameters of the root mean square values of AE signal (AERMS) are used to monitor tool wear. The rubbing between the tool and the workpiece increases as the tool wear crosses a threshold, thereby shifting the mass of AERMS distribution to right, leading to a negative skew. The increased rubbing also led to a high kurtosis value in the AERMS distribution curve. © 2012 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Meenakshi G.,CSIR - Central Leather Research Institute | Sivasamy A.,CSIR - Central Leather Research Institute | Suganya Josephine G.A.,CSIR - Central Leather Research Institute | Kavithaa S.,Central Manufacturing Technology Institute
Journal of Molecular Catalysis A: Chemical | Year: 2016

ZnO/SiC nanocomposites were fabricated by a simple sol-gel process for exhibiting an enhanced photocatalytic activity under UV and visible light irradiation. The prepared photocatalysts were characterized by XRD, UV-DRS, FT-IR, AFM, FE-SEM, EDAX, HR-TEM, SAED, XPS and EPR analysis. XRD and FE-SEM showed that the prepared photocatalysts were nanocrystalline. Band gap energies of synthesized ZnO/SiC composites were calculated using diffuse reflectance spectroscopy (DRS). High surface roughness and porosity were confirmed by AFM analysis. The XPS survey spectrum clearly revealed the presence of Zn (2p), Si (2p), O1s (530.2 eV)and C (1s) in the prepared composite material. ZnO/SiC photocatalyst produced OH radicals instantaneously within 60 s and 15 min for UV and visible irradiation respectively when compared to 180 s and 30 min for pristine ZnO which were confirmed by EPR spin trapping technique. This fast rate of OH radical formation is due to the presence of charge transfer mechanism in the prepared ZnO/SiC photocatalyst. The photocatalytic efficacy of the prepared catalyst was studied for the degradation of phenol as a model pollutant in the aqueous phase. The photodegraded samples were analyzed by UV-visible spectroscopy, COD analysis. ZnO/SiC nanocomposites showed a two fold increase in photocatalytic activity compared to pristine ZnO and reusability without affecting its performance upto three cycles. It also followed a pseudo first order kinetics. © 2015 Elsevier B.V. All rights reserved.

Kavithaa T.S.,Central Manufacturing Technology Institute | Balashanmugam N.,Central Manufacturing Technology Institute
International Journal of Advanced Manufacturing Technology | Year: 2016

The evolution of ultra precision finishing processes due to the continuous demand of stringent functional and technological requirement of the components has led to the emergence and development of the non-conventional abrasive flow finishing (AFF) process. This could be attributed to the need for relaxation of tool limitations: precise finishing of complex geometries and internal passages in typical industrial components. Herein, the abrasive laden polymer conforms onto the work piece geometry due to its flow characteristics overcoming the shape limitations inherent in conventional finishing processes. The paper describes nanometric surface finishing of typical prosthetic implants and an extrusion die used in bio-medical and pharmaceutical industries, respectively. Finishing and deburring of a propeller and a shuttle valve used in aerospace applications are also discussed. The study highlights the possibility of successful extension and implementation of AFF process in simultaneous ultra precision finishing applications of industrial components. The versatility, functional, and stochastic aspect of the developed AFF system in surface finishing of ferrous and non-ferrous components is also emphasized. © 2016 Springer-Verlag London

Ramesh C.S.,PES Institute of Technology | Ramesh C.S.,Bournemouth University | Keshavamurthy R.,Central Manufacturing Technology Institute | Koppad P.G.,PES Institute of Technology | Kashyap K.T.,PES Institute of Technology
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

Studies on texture and microstructure evolution in hot extruded Al 6061 aluminium alloy reinforced with uncoated and nickel coated SiCp were carried out by electron backscattered diffraction technique. Textures of both the alloy and its composite with nickel coated SiCp do exhibit strong β fiber with its axis parallel to the direction of extrusion. In addition to the dominant cube texture (001)〈100〉, fully recrystallized grains with partially equiaxed structure have been observed in the alloy reinforced with uncoated SiCp. The recrystallization texture of this composite can be attributed to the particle stimulated nucleation (PSN) due to the presence of SiCp with size less than 5 μm. Under these conditions, the low value of Zener-Hollomon, Z (∼ 1012 s-1) confirms that PSN is one of the dominant mechanisms for recrystallization and is governed by formation of deformation zone rather than stored energy. © 2013 The Nonferrous Metals Society of China.

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